Don't buy anything till you're good and ready and happy with your choice. A lot can be tweaked, but not everything, so you really do want to start with a bike that fits well. Proper fit really matters. There's a plus to having a woman cyclist about your size helping you pick, I think. Ask her what OTHER brands she might recommend, to see if she's able to discuss bikes beyond Bianchis.

I have a Bianchi Eros Donna and absolutely love it. But that's not the point--point is, do more test riding, search on some threads here for fit discussions, and follow your best instincts too, not anyone else's pressure.