Being unsatisfied with her glasses will make her more likely to care for her contacts.
If your teen generally practices good hygiene she will be more likely to be diligent about eye care as well.
Does she sit down to do her homework without being prompted, does she tell you where she is going with friends and call if she is going to be late? Teens need to be mature enough to insert, remove and clean their contacts daily. Disposable contacts will minimise this effort but can be more costly.