Yeah I am 22 and no-where near being a parent, but the first thing I think parents have to understand is you cant force things on to teenagers. Cause do parents like the pressure of everyday they get forced into. No one wants pressure. Sure, its a lot of money out of the pocket for contacts(I know to replace a lense without insurance on my glasses). The choice though has to be hers. I love glasses and cant see why people want contacts, glasses are awesome. I have the darkest rings around my eyes, and for the longest time. Tell her people all over the place have them. Its a good sign of being tired!"say it as a joke"
Oh yeah you might want to find out if umm, the contacts bother her though. It could be one of the issues where they bother her but she will feel like she has dissapointed you by saying that. So she makes up the store about the eys and everything. You never know unless theres a real good relationship to a teenager with a parent.