plog is right, all that matters is the interest rate.
You might use this as an opportunity to see which psychological method works best for you. Anything that motivates you to save or invest is a plus.
Some examples:
-Pay the smallest balance first so that you knock it out the fastest and have "fewer loans".
-Pay off the oldest semester first so it feels like "paid off freshman year", etc.
-Pay off in chunks that make the loan balances nice round numbers, if only for a day.* (My husband liked this one.)
-Pay down the largest balance until they're all equal.
-Roll a die and pay down the "lucky one". See which loan finishes first.
Make it a game and you'll stay motivated to pay them off to the end.
*Just make sure you always pay an amount that exceeds the accrued interest. If you have $1,000 in loan principal that accrued $25 in interest, don't make a $20 payment since this won't even cover the interest. A $30 payment is okay though because it hits all the interest and some of the principal.