What shall i do after 12th if I am interested in chemistry?
I'd say you go for a Bsc, if you want to teach chemistry someday. It'll be better for you.
But if not, then pursue chemical engineering from a tier one or two institution. This way, you keep other options open, while taking the joy of chemistry every day.
Bsc in chem
Or chemical engineering
You can pursue B.Sc. in Chemistry hons. Or B.Tech. in Chemical Engineering Branch.
If you want good College, then you have to appear in JEE Mains. Through this you can join B.Tech. Or integrated B.Sc. and M.Sc. Course in IITs and IISERs.etc.
You can also Join any central university for B.Sc.
Good Luck.