It should only start incurring interst after you graduate college. Most student loans usally have those terms where you don't need to pay untill you graduate from college, then give you a pre-set amount of time of grace period after graduating to start paying on the loans. Call your college finicial office and they can help explain to you what the different terms mean. You can also try looking up your type of loan on the federal student loans page and see if that question is covered in FAQ, if not they should have explainsions of all terms.
If the college phones are constantly busy, phyiscally go to the office and ask for explanation of terms. Don't let that busy signal stop you from getting the answers you are intitled too.
Me personally I stay away from loans cuz i don't want to be in debt after graduating. I do my purely on grants alone.
Most college you can do that on but if you go to a private tech school they usally charge much more and grants alone won't always cover all expenses.