trading babysitting

I've started to trade babysitting with another mom, who is taking graduate classes. I was finding it really hard to work and keep an eye on J. at the same time, and I hated being in the middle of working and then having to just stop suddenly if he woke from his nap. So I had started to look for a part-time nanny, but in the process of doing that found out that my friend was also looking for someone. So we worked it out that I have her son here two half-days a week, and she'll have J. two half-days a week. The boys are about 2 months apart and play really well together - I just finished my two half-days for this week, and then she'll have J. tomorrow afternoon.

The only thing about this that I'm not sure I'm going to like is changing another kid's diaper. I used to babysit all the time when I was in high school and college, and even worked at a day care one summer, and I don't remember having this strong dislike of changing diapers. And I could care less about J's diapers. But it almost makes me want to puke every time I change this other kid's diaper. I'm wondering if his mom would think it was strange if he had a wet/dirty diaper every time she picked him up?