She's 5'2". Looking around the sites regarding sizing 48cm seems about right. It may be a bit off but I'm assuming we can change some things out if necessary. Also given that this is her first road bike I'm sure anything will be an upgrade over the mountain bike. I understand exact sizing is quite important for those doing a ton of riding but I couldn't see her using this more than for a few tri's and short bike runs (26 miles or so). So I'm assuming this would work working off of the fact that she's 5'2" and that she has sat on a newer model of this same bike and seemed to be fine with the fit.