Dear Shubham,

You should opt for science in 11th. Even if your interest fluctuate after 12th you can switch over to commerce and arts branch. But you cannot do the other way round. Make your basic clear in PCM/PCB. After that you have a lot of scope depending your intrest:

1. B.tech in Agriculture
2. BA llb
3. BSc+MSc+(PhD)
4. B.ed+M.ed
5. Engineering
6. Medical
7. Architecture etc.

And science is lot easier as compared to commerce and arts. The competition is also less in science stream as there is a lots of scope. But the scope to completion ratio of commerce and arts department is very low as compared to science.

I think it's helpful for you 

Best of luck.

It's depend upon you but whatever you decide for that you should get a hard work according to your stream but if you take commerce you have a much opportunity for any field so.all the best

see the equation is very simple that you can switch from the science stream in class 11 and 12 to a commerce or Humanities stream at your college level but it will not be possible for you to opt for the other way round
if you take science in class 11 and 12 you have medical options ranging from medical as in MBBS, dental as in BDS, physiotherapy as in BPT, ayurved or alternate medicine such as b a m s and BHMS as well as general science courses ranging from biochemistry, microbiology, zoology and biotechnology
you could pursue your graduation post graduation and doctor degrees on them and be involved in research work, executive work as well as undertake professorship on your subject of mastery
yes if sides does not suit your aptitude you can definitely shift over to some Humanities or commerce line later on