Do I have to choose only one, because I'm totally confused of where to put my maximum focus on, can't i prepare for both simultaneously?
And yes, i have equal interest upon doing computer engineering and MBBS too? So, where should I move to? Or, can I go for other options taking both biology and mathematics in future (because I don't have much idea on these matters and of exams which are taken which includes both biology and mathematics)?

Let's just say you prepare for both the exams and you clear them. But afterwards you can take admission only in engineering or only in medical. Preparing for both the exams that is NEET and JEE Mains ; the physics and chemistry portion are almost similar. The different subject would be mathematics for JEE Mains and biology for NEET. So you would have to work extra harder to clear both the exams.Now there are many students who are preparing for only one exam. This becomes a little tougher when you want to do both of them as your time would be divided into physics, chemistry along with biology and mathematics. Now if a student wants admission in IIT (Indian Institute of Technology) then he/she has to clear JEE Mains along with acquiring high rank in JEE Advance. JEE Advance preparation needs a lot of practice and time. If you want admission in IIT then I would suggest you to focus only on JEE so that you can get admission in branch of your choice. For NEET every year the cutoffs for MBBS in government colleges are pretty high (550+ on 720).A student can also take admission in private colleges for MBBS which have a bit low cutoff but the fees of private colleges for MBBS are very high when compared to government colleges. Since the competition is high you need to practice more. To practice more, more time is required.It shouldn't happen that a student clears both the exams but wasn't able to score high enough to get admission through any exam in his/her choice of course due to focus on many subjects. There are some courses in engineering which require biology too. But a student must have interest to do it. For example :- Biomedical Engineering. Biomedical engineering program comprises study about tissue engineering, molecular or systems level biology/ physiology and mathematics. It tells us about biomedical electronics, quantitative and analytical skills required to interpret data acquired and processing of medical data including imaging and enhancement techniques. Other aspects of the program include the study of biomechanics, cellular engineering, genetic engineering, orthopedic surgery, bio-instrumentation, medical imaging and bio-materials. There is also other course called Biotechnology engineering. This isn't to give you tension. Don't be stressed. Take some time discuss it then choose. What would you like to do more than the other?See the syllabus of the courses and then choose where your interest lies. 

Thank you..this really helped me a lot being a student of class 11.
Now, I've made my mind for MBBS and that too from government colleges, but if my marks do not meet up the cut-offs by government Colleges, then what should I do, else can I go for other courses of engineering which requires biology, does they have scope in India(for ex- biotechnology, biomedical, etc)?

Please, give a reply!!

Try your best to score high marks in NEET. For MBBS in government colleges the cutoffs for general category are 550 and above on 720 (it changes every year). You have time and you can score well if you prepare from now on. Now if a student is not able to meet the cutoff for MBBS in government college then he/she can apply for other medical courses in Government colleges (provided the marks are above cutoff for that courses). The courses other than MBBS after NEET are as follows :-BDS (Bachelor of Dental Surgery)BHMS (Bachelor of Homeopathic Medicine and Surgery) BAMS (Bachelor of Ayurvedic Medicine and Surgery) B. Pharm (Bachelor of Pharmacy) BPT (Bachelor of Physiotherapy)A student can choose from above courses if he/she is not able to meet cutoff for MBBS. As you said you are in 11th I suggest you to start preparing from now itself. Everyday cover some syllabus of the entrance. To get MBBS in government college is little tough but not impossible so start studying from now on. Now for engineering as asked, in engineering too there are private and government colleges. Almost every private college has it's own entrance exam to get admission in engineering. For example SRM Institute. It is a private institute with its own entrance which is called as SRMJEE. For private institutes the criteria for biomedical or biotechnology is different every where. Some give the admission on the basis of marks scored in entrance with combination Physics, Chemistry and Mathematics whereas some give on the basis of Physics, Chemistry and Biology. In NITs, IIITs, GFTIs the admission is on the basis of JEE mains. Now if you want biotechnology or biomedical engineering in these mentioned institutes then you have to give JEE Mains (Physics, Chemistry and Mathematics).If suppose a student is not able to meet the cutoff for biomedical or biotechnology then he/she must be prepared to opt for any other branch.Do not get confused. Again I'm saying choose wherever your interest lies. Make your decision and start preparing.

Okay, I'll start preparing from now onwards. But , as you said, I should cover some sort of the syllabus for the entrance everyday, so , where should I start from?I mean what books i should prefer? Should I buy MTG NEET Biology or Arihant NEET Biology? Because, these books are summarised as NEET syllabus and contain mainly objective questions as per NEET questions and yes, they do contain the previous years' NEET questions too.So, I thinking I would go through these books after completing each chapter from NCERT.
So, my question is how should I prepare and which books should I follow?



And yes, how would I manage my time with maths,then? I'm totally confused what to do, because in 11th I didn't had much pressure, I had given equal importance to these two? But after seeing syllabus of maths and biology I'm confused where to go. Because, I guess biology would be easy as I've studied most of the topics in class 10 itself.

You should start from NCERT textbooks of 11th and 12th standard of Physics, Chemistry and Biology. For Biology :- Make notes of everything you study. The diagrams in the textbook are important. Practice them. Study a chapter then solve the objective questions of that chapter. Books for Biology :- Trueman's Elementary Biology, Objective NCERT at your Fingertips (mtg) are good books which can be referred. For Chemistry :- Again make notes of chapters and formulas. Chemistry is divided as Physical Chemistry , Inorganic Chemistry and Organic Chemistry. For Physical and Inorganic Chemistry practice numericals, formulas and remember everything.Books for physical and inorganic chemistry are :- Numerical Chemistry by RC Mukherjee, OP Tandon Inorganic Chemistry, JD Lee Concise Inorganic Chemistry. In organic chemistry there are many different types of reactions which can be remembered only by writing. Start from basics of the reaction write them everyday then go on to difficult ones. Books for organic chemistry :- Organic Chemistry by Morrison,  Organic Chemistry by G. R Bathla and Sons. For Physics :- Physics is a subject in which no question can be answered well if concepts are not clear. So when you are learning concepts if any doubt arises then get it cleared at that point of time itself. Books for Physics :- Fundamental Physics by Halliday, Resnick and Walker , Objective Physics by DC Pandey.Reference books are good but first a student must study from NCERT textbooks.Solve multiple choice questions everyday on some or other topic of each subject. Prepare a timetable and try to finish portion as early as you can so that you can get enough time for revision. You can get these books from library too so no need to buy all of them. Now in NEET the main subjects are Physics, Chemistry and Biology. So you need to study mathematics according to Boards portion. Give time to mathematics also. Everyday some time to it. Most of the part is solving sums so you can do your entrance portion and in between fit in time for mathematics. Stress is of no use as it only brings problems. Study well.  

Thanks a lot for helping and clearing out my doubts.