AITA for confronting my SIL for getting my child sick?

I (22F) am typically a confrontational person except when it comes to my in laws. For the most part, we get along great. The only exception being my husband’s (23M) older and only married sister (27F). For as long as I have been with my husband, she likes to be in control of the situation, and since she had kids before the rest of us, the whole family has pretty much revolved around her family’s schedule. I can get quite annoyed at times now that my husband and I had a child about 7 months ago. However, my husband lost his dad a couple years ago, so his family is very important to him, and thus important to me, so I usually just let these instances slide under the rug. For the record, my husband also gets annoyed with his sister a lot but isn’t confrontational so he doesn’t talk about it with her. We were with his family all Memorial Day weekend. My sil’s kids love having a younger cousin, so they spend some time playing with my daughter as much as one could with a 7 month old. Monday, around dinner time, my daughter was playing in the grass with SIL’s 10 month old son. He had his fingers in his mouth, and then put them into my daughter’s mouth. After the first time I just would block his finger from going into her mouth. After all of this, my SIL tells us her 10 month old and another child have been sick for several days. Looking back, I noticed her kids had runny noses, but I honestly just thought it was regular kid runny noses. Later in the week my daughter got sick and it’s hitting her hard. Lots of coughing, congestion, and bowel issues. She’s typically a great sleeper, but now is needing a lot more comfort so she only sleeps at night while we hold her. This has led to several sleepless nights in a row for us. And now, I am sick. I have a big commitment this weekend and am now afraid I will either be too sick to go or completely exhausted while I am there. But both my husband and I were frustrated with his sister and brother in law. My husband texted her asking how long her children were sick for and she got the hint and apologized saying “I hated it when people got my kids’ sick”. I finally texted her saying it was inconsiderate for them to bring her kids without telling us they were sick, and that the least they could have done was warned us before so we could have either chosen to stay home or make sure her kids stay away from our daughter. She doesn’t handle confrontation good (which is why I’ve always avoided it in the past with her), so she replied with “yeah sorry” and now is telling her family how over the top me and my husband are. I know that it wasn’t the end of the world that my daughter is sick, so should I have just said nothing because it isn’t going to change the fact my daughter got sick, and now all it’s done is ruffled feathers? AITA