You are fortunate...you live in an area where there are quite a few bike shops that carry bikes designed for women and their measurements...visit a few of your local LBS's. Sit on a few. IMHO, the 27.5" wheel size will probably feel better than a full 29'er, and you get some of its benefits over a 26"-wheeled bike. The LBS's in Tustin, Irvine, and Lake Forest will give you a good range and quick education on what's possible and also who she can ride with...there's quite a few women's groups that ride regularly.