If you don't mind, can you tell me what your credit score was, and if you were approved without a co-signor and decided to go with a co-signor because of the cheaper rate. I am looking to use them and really do not want to use a cosignor regardless of what the rate may be.
My credit score was in the low-to-mid 600's...I'm only 21 and haven't had my accounts for 3 years (which seems to be a major threshold for creditors). I'm guessing Citi's cutoff is 650 or so and I just missed, but that's just a guess. I needed to have someone co-sign.
I know co-signing is a last resort (it was for me), but if it can lock in the lowest rate possible for 5 years worth of interest, I think it's worth it. Also, you have a couple options with this route: 1) You can always just go in on your own next year, and just have this year's loans co-signed, or 2) You can co-sign all 3 years--but Citi has a program (as do some other lenders), such that if you pay your 1st 24 payments on time, then the co-signor is released of all responsibility and the balance is transferred to your name for the remaining life of the balance (still with the same good rate).
In sum, if your score isn't in the high 600's or 700's, you very well might need one. Do your credit research thoroughly, if you haven't already. I made the mistake of assuming my "PLUS Score"'s that the reporting agencies were giving me were the true thing (they said I was in the 680-710 range); make sure you find out your actual FICO scores (this will cost $$).