Is it possible to graduate from a 4 year college in 2 and a half?

I'm sorry, but the answer really is a maybe. It will depend on your school and your major. You can get in enough credits to graduate in two and a half years, but some colleges won't allow you to finish that fast, and you also might have trouble with getting the right courses to complete your major, because some of the advanced courses will have pre-requisites.