Hii,

Anyone can get btech admission if he /she has completed 10+2 with minimum percentage of 50.

As you are having 54% it is sufficient to get admission in BTech.You can get the admission in btech in any state through JEE mains exam .If you have want to join in a particular state college then you need to write that particular state Btech entrance exam.

Don't worry about your previous marks.Study well and get good marks in the future exams.

All the Best...,