Hi, Since you got 15500 rank you can go for many good colleges but sorry to say not for NIT. Yes you may try for lower ranked NIT's but there also you may have to satisfy with the branches that you have might to take. So I suggest you rather to go for NIT you should go for GFTI's. You may get your desired branch there also you should not be limited to Andhra Pradesh only you need to also go through other colleges as well situated outside of your home state.

Yes you can also predict the choice of your college according to your rank fro Careers360 College Predictor tool(link is mentioned below);

https://engineering. careers360.com/jee-main- college-predictor?icn=QnA&ici= qna_answer

GOOD LUCK.