Mom Here, Sitter Couldn’t Change Diaper?

I moved a little under a year ago and used a babysitter for the first time since moving, so a new babysitter. I told her my kids ages before she accepted the job. My youngest is a literal baby so diapers weren’t a surprise. When I got home the baby was in a diaper that was just being held up by her pants. One of the tabs was ripped off and on the kitchen table, the other was not opened whatsoever. So the diaper was not closed at all, just kinda folded over her.

This was an adult. She did look young but mentioned a husband and was available during daytime hours for my appointment. If I saw her on the street I’d put her about 16. She supposedly has experience, her reference who I know personally has five little kids.

I really don’t want to have to look again. Should I show her how to change a diaper? Is there a good way to bring this up? Does she think she can change diapers and this will be conflict? Should I just find someone else?

I’m in the “your job is to keep them alive and that’s basically it” camp and afaik I pay market rate.