Hy,

Getting less than 60% will make a difference, if you look for JEE as IITs do not accept candidates scoring below 60% in 12th.

You can get admission but in good colleges.  you might have to give a simple entrance test also. You can also appear for IIT JEE .Just check for some good sites to see the details of the admission procedure in the web sites of various sites like RV, LPU, PES , VITEEE etc.

Hopes this helps.

Wish you luck