First thing you need to do is to get good grades in 12th, try scoring at least 80%. Fill up form for JEE Mains and appear for the exam, no matter what. If somehow you're able to score good marks then look for colleges where you can get admission through your JEE Mains rank and if not look for a good private engineering colleges.

Or you can research a little bit and try to know about your interest.

Then choose something which you like.

Feel free to ask if you have any more queries.

All the best!