Wolff's law is in reference to healing, and why our bones simply don't just remain shattered. My arm is an example of that when I broke it several years ago. However when taken into your context, I went to NCBI (Which is a real source, not Wikipedia) for my rebuttal to your argument.

[url=http://www.ncbi.nlm.nih.gov/pubmed/15605390]A real source.[/url]

Wolff's law explains how at the breaking site, it would be slightly stronger. In order for your entire bone to become stronger, you'd have to break it in area. Then doing that on the entire skeleton? Don't even try. That, and breaking your bones leads to other health problems later on down the road. So if you want your character to be a little old lady at the age of seventeen, be my guest.

Drawing comparison to other people's powers shows your are desperate to be ratified in some odd way. Your argument is incredibly flawed and in essence, limits your character in far more ways than it benefits you. If you want to keep your stronger bones I'm also going to have to ask you to edit your character to have all of these health problems:

[url=http://www.niams.nih.gov/Health_Info/Bone/Osteogenesis_Imperfecta/type_1.asp]Osteogenesis Imperfecta[/url]