I don't know that it would have discouraged a very determined young dancer. From what one can glean from the article she was always somewhat ambivalent about ballet. Perhaps all those absences speak for themselves.
Yes. I should have said "a driven young dancer," not "very driven." To be a professional you have to NEED to dance, not just like to perform.
As for the absences, I do wonder why she was so frequently absent. When I didn't want to go to ballet when I was a kid, my parents made me go anyway. It does seem like she had absent parents and that there's more her family background than the Times story went into.