Rejecting financial aid loan offer vs accepting it and paying off a different loan

Potentially a very stupid question, but here goes.

I currently have about $7,400 in loans (both Federal Direct Subsidized Loans, one $2,900 and the other $4,500 if that makes a difference). I recently received my financial aid award and was offered a Federal Direct Subsidized Loan for $5,500.

Now, I have about $5,000 in my bank because I didn't need to use the previous loans I took out. I did some calculations and I should be able to manage rent and tuition and other expenses without taking out the loan.

Here's the stupid question. Should I take out the loan I'm offered, and pay off one of the loans (it would be the $4,500 one), I'd be left with about $500 in the bank or so plus the money I receive (all grants) after paying off tuition (this would be used for rent and other expenses).

OR should I not take out the loan and make due with what I have in my bank? (I would also be left with the grants I previously mentioned after paying tuition.)

I'm pretty sure paying off loans helps with credit scores, so I'm leaning towards the former option. Does it make a difference? Oh and also for the first option, paying off the loan while in school doesn't automatically start my monthly payments, right? I'd still have the 6 months grace period after I graduate (entering my third year, so in two years)?

Thank you!