Everyone is different. Some children and adults, won't be bothered/influenced by just going to a few meetings. However, there are instances that can affect children very deeply and you won't know about it.
From my own experiences growing up in this religion, I accepted what was said from the platform because I was told lying was bad, lying about God was punishable by everlasting death. So of course, things said at the hall, were going to be true otherwise they would suffer eternal death.
We had books that showed death and violence to those that didn't serve God. Peer pressure. Constant encouragement to not live life now but wait till God makes things right on earth.
One of the saddest videos that they have put out recently, shows a young child being offered a chance to expand his abilities to play the violin with other "worldly" children. His father continually pressures him to not do it till in the end, the child turns his back on the opportunity. Just so he can spend more time with god. Almost everyone that has grown up in this religion, lost out on their true creative abilities because of the Watchtower strongly discouraging doing anything other than going to meetings, go out in service, study the bible.
You can skip to 6:07 or so if you just want to see the clip. (thanks to berrygerry for posting it here)
https://www.youtube.com/watch?v=HNzgd8Oa2rE
My nieces were visited by their grandparents a few years ago. Their mother had been "disassociated" before they were born and she was shunned by her parents. So when they came to visit, they took them someplace fun but then showed them the video that has been posted here of the boy with the "magic" toy. When they came back, they went in their room and began to cry. Why? Because they were going to have to throw away their toys they loved that were "magical" or suffer God's wrath. One video. One time.
So I would say if you want to take the chance to let them have alone time with her, take her to meetings, I would have a discussion about how you would like to hear about what she did with them. What did the meetings talk about, how did she feel about those subjects. And I would do it every time she went. Children are sponges as they say.