Why or how did she get famous?

Demi Lovato started out on Barney. A couple of years later she was on As The Bell Rings, a little 5 minute show on Disney in between shows. Well, my theory is that when Selena Gomez, her friend from Barney, got her own tv show (Wizards Of Waverly Place), she decided to audition for Camp Rock out of jelousy but I could be wrong. But what I do know for sure is she is a heck of a lot more talented the Selena, singing and acting wise. So, Disney realized that and gave her her own show. (Sonny With a Chance) I think she deserved it. Well another thing is that when Demi started singing Selena tried to sing even though she's not very good at all. But, that's another story.