had been / was

“She had been a ballet dancer in her youth.”
Is this sentence correct?
Since we use past perfect (‘had been’), it should have double events.
So can I say it is wrong?
So this sentence must be simple past as below:
“She was a ballet dancer in her youth.”

Both sentences are possible.

There is nothing wrong with ‘she had been a ballet dancer in her youth’ providing there is a continuance of the conversation somewhere which indicates the reason past perfect is used.

She had been a ballet dancer in her youth. Unfortunately knee problems ended her dream of turning professional.