Are these federal loans? If so you can login to this Dept. of Education website and it'll show you all of the repayment options you have, and how much your monthly rate would be under each.

There are too many unknowns to give you any solid advice (like gov vs private loan, the interest rate) but the general rule of thumb would be paying more earlier is better, because that's less debt accruing interest which you'll be paying back later.

But there are other things to consider, like public service loan forgiveness (if you truly intend to be at a public school or 501c3 private school for 10 years), where it would behoove you to not make large up-front payments.