When should I look for a new placement

I have been a trainee dental nurse since last month and am really enjoying the work but not keen on how I am treated there. I feel like I’m not learning as much as other people. I need to be put on this course but the person who owns the dental practice doesn’t want to pay out for the course until next year as when I qualify they will have to pay me more an hour so they want to pay me as little as possible. Should I find another placement or stay and gain experience and look in a few months?