Yup, this is a targetted offer so only some people are receiving it.
50k is a good way to welcome them to the world of credit

I'd recommend going with it, especially with the fee waiver on the first year. You should help her evaluate if the annual fee is worth it based on her spend once the renewal comes around.
Remembering my college days, I couldn't justify a card with an annual fee with my level of spending. If I were in college now, I'd probably get a Citi Forward card, as it pays 5% back on books (textbooks are expensive), movies (no, not that kind), and restaurants (because the tequila bar down the street is classified as a "restaurant").