Take a look a the following passage, please:
Jane had always wanted to be a nurse ever since she was a child but her father had told her that nursinbg wasn't a suitable profession for her to follow. Having left / leaving school, she was offered a job working as a doctor's receptionist.
I wonder whether I could used
"...hadn't been a suitable profession for her to follow."
We are talking about the time before her graduating from school (about the time "her father had told her..."). Although it is so, the moment when she needed to chose her profession was much later.
Before answering my question, please, make allowances for be because of my not native origin.