Amy,

Funny you should ask! I was worried as well (I'm short and have some neck issues that necessitate a shorter top tube). Anyway, this is the info that CC sent to me:

Geometry - Via Nirone 7 Alu Carbon
Size, mm
500
530
550
570
590
610

Seat Tube, mm
470
500
520
540
560
580

Top Tube-virtual, mm
530
540
555
565
580
590

Top Tube-actual, mm
515
527
541
552
568
577

Btm. Brkt. Drop, mm
68
68
68
68
68
68

Head Tube, mm
120
135
145
165
180
200

Seat Tube Angle,°
74.5
74
73.5
73.5
73
72.5

Top Tube Slope,°
7
6
5
5
4
4

So, I would suggest comparing this to your current bike (which, I assume fits you) and then choose the Bianchi that best correlates to your bike's geometry. Jewel said they do have a new smaller size that will probably work for me (she's working on getting the exact geometry), but I'll probably need to bring my own stem.

Hope this helps!