I am not sure what your religion is, but for the purpose of clarity I am a Christian and believe in the triune God portrayed in the Holy Bible. I have recently graduated high school.
I do not know why God allowed some people to become ballet dancers and not others, but I want to mention that although there was a time I wanted badly to get into a professional ballet school and become a professional ballet dancer, I am now glad I did not end up doing so. There are things that are to me far more important (for example serving God and others) than my past dream of dancing professionally on stage. For one, not fulfilling what was once my dream has allowed me to develop other interests. Having said that, I understand that it may be painful to realise your dream may never come to pass.
While I don't know that the dream of becoming a professional ballet dancer is the most important thing, I believe that with God nothing is impossible (I believe that with God nothing is impossible (Matthew 19:26), and that if we delight ourselves in the Lord, He will give us the desires of our heart (Psalm 37:4).
I am not suggesting you should necessarily pursue these as career goals, but I want to mention there are dance related fields that do not necessarily involve dancing professionally on stage.
To answer your question, really, I don't know. I wonder if you have prayed to God or talked to people around you about this?
I personally think that as long as you have tried your best, that should be enough.