haha, Squid is right, it'll start squeaking and creaking alright but if she's set on that bike, what can you do. My wife wanted a bike, I knew she'd only use it several times a month MAYBE, so I got her the Schwinn 7 speed Roxie from the local Target ~$160 (she wanted a pink bike). Not a good bike, every now and then I wrestle with the crappy derailleur getting it adjusted just right, but it works for her and it works really well as long as the tires are pumped. She enjoys it, it's pink and has nice chrome (for now) fenders and white walls (I could have spent $500 and if she didn't like the color it wouldn't have mattered how much better the bike was!). There's a lot of really nice bikes sitting in garages all over this land!

Note, the cheaper bikes often have a pretty small frame so indeed have her sit on it and see if it feels too small. Also plan on upgrading the seat, they are often hard as a rock on the cheaper bikes. The right seat makes everything nice and encourages people to ride.

Keep those tires pumped up and the chain lubed and she'll probably enjoy it.

Good luck.