I applied for an Amex Blue for Students during my freshman year of college. They gave me a $2500 limit, but I think that's because I have high balances in both my checking and savings accounts. I didn't have much (if any) credit other than the accounts (if they even contribute to my score at all).
I think that if you have a credit card, it's imperative that you HAVE A JOB too. Otherwise, it'll be all too easy to rack up the debt without any income. I've had a job from the time I was a freshman in high school, so that might also have contributed to my high score.
That said, Amex Blue for Students is a great card - the main benefit for me is the one-time-use credit card numbers. Great for shoddy magazine deals and weirdo internet retailers. Not that I shop at weird places or anything.
