Hi
Of course we don't know about a 2nd gen Air, as you can see, the "guessing" went wrong with all of us hoping that today the new iPhone was going to be released, so all I can give you, is like you say, an educated guess.
Here's what I think. The Air has been very recently released, and it's still in the "wow!" period, I believe that if there's an upgrade, it would happened at least, by the end of the year, and that's a long shot, plus, being sure of that is impossible, since Apple keeps everything ultra top secret...
My advice is, she should get a MacBook. There are almost confirmed articles about a new MacBook being released by the 3rd quarter of this year (all aluminum and stainless steel like the MacBook Pros). The thing is, the laptop has the same dimensions as the Air (13.3 screen) but it's a little bit thicker and heavier. But not "that much". The thing is, it has a much more powerful processor (1.8 vs. currently 2.4 and it will be even faster), much bigger hard drive (More than 200gb compared to the Air's 80 or 64 gb) and much more RAM Memory (4gb vs. 2gb).
I consider the Air to be a novelty item, I mean, yeah, it's light and thin but if she's gonna be using a computer for college, she needs a fast machine, with powerful components and large storage.
Plus, there's a HUGE price difference for this "lightness". You will be paying more than 3000 dollars for the top of the line Air compared to the 1600 you will pay for the top of the line MacBook. If she's willing to spend that much, she should consider getting a MacBook Pro, where there's a good Video card as well (better than both the Air and the MacBook's).