Question about maternity leave?

So I work at a daycare and I’m on maternity leave until March 4th. On February 18th there is an all day training at another center. I wasn’t planning on going because A.) I’m on maternity leave and B.) I don’t have a babysitter.

My boss texted me today saying I have to go. I told her I didn’t have an all day babysitter and that made her pretty mad. She told me I’m going to have to go to a completely separate class and pay for it.

Does this seem fair? I’m totally okay going to a training but I don’t feel like I should have to pay for it. I’m already not getting paid for my maternity leave.