I recently purchased a Bianchi Piaggio on craiglist with the intention of converting it to a FG for my girlfriend. Before I ordered a new wheel set online I decided to make sure my own 700c wheels fit on the bike. The back worked fine, but when I put a front wheel on, it seemed like it was about 1-2mm too long for me to be able to get it on. The Bianchi initially had 27x1 1/4 wheels.

I did a bit of an experiment, I took the 700c wheels and they fit on my own older road bike, which also took 27x1 1/4, and it fit. The wheels from the road bike also fit onto the Bianchi. The original Bianchi wheels fit onto the road frame as well. I'll note that my girlfriend is short, and the frame is a 48cm. Would I be better off ordering her a 650c wheel set (which I also have the fear of not fitting the mysterious front fork) or do I just have a problem with my wheel? Something with my fork?

I have a decent amount of bicycle knowledge but I'm far from an expert, so any help is appreciated. Thank you!