Kids during the first dance?

My fiancé and I decided to not do a kids free wedding in order to not offend our family members. We will be having a small wedding and not many of our family members have kids so luckily there won’t be too many kids to worry about. However, my biggest fear since the beginning was that kids would start playing on the dance floor during our first dance since I’ve seen it before. For our first dance we will be having a fog machine to make it look like we are dancing on clouds and I can only imagine how fun it will look to children so I don’t blame them. Is it rude to tell the parents beforehand to be please watch their kids during our first dance because the fog will look fun but we want that moment to be ours? I figured we’d also have the DJ announce it that day but I wasn’t sure if it’d be rude to also tell parents casually during a conversation as they are all very closer friends and family members