Diaper Changes

So I work at a daycare, and I am the lead teachers for 3's. However lately 3's and pre-k have been combining, which gives me another teacher. There's a few kids that still have diapers, and not just in my class. However anytime a child uses their diaper I am always the one that changes it, no matter what. The other teacher will always ask me to do it. I don't wanna be rude so of course I agree.

However the other teacher has their own child that attends the daycare that is still in diapers. The teacher will only ever change their own child's diaper.

Am I overreacting and should just keep my mouth shut and just do the job?