I think she was too immature when she had it.
This may be a weird analogy but it is like braces... everyone I know had braces at 12/13 and never wore their retainer afterwards because they are lazy. Their words, not mine... I got my braces fitted at 17 and since they got taken off 4/5 years ago, I have never skipped my retainer. I even take it on holiday with me! I can't say I would have done that if I wore them at 12.
What I mean is, she was far too young/immature to deal with the responsibility of maintenance afterwards. This was obviously a lot more serious than braces, but I'm trying to highlight her laziness.
I'm not convinced that if she had the surgery tomorrow she would have the discipline, either.