I come from a long & proud Army tradition.
However, of all of the females I've know in all of the branches of the military, I'd say that the Air Force is the way to go. They have great assignments and are less sexist (LESS, not totally UN sexist). Especially for the prettier girls (which is the group she of course falls into).
I wish her the best with her decision. May she be proud no matter what she chooses.