AITA for not inviting my friend's daughter to my birthday party?

Hi! Sorry for my poor English, it's not my first language. So today is my birthday (f28) and I invited my coworkers/friends to my house to cook some sushi, drink some wine and have some chill time (it's summer here so we are on a break, nost working currently). I am married and have an 18mths old baby boy. At my job there's this girl who is my age (f27) and a single mother to an almost 4yr old girl. She usually leaves her with her parents or brings her to social meetings (without asking, asuming everyone can and wants to accommodate her daughter). I consider this girl a friend but not a close one... Yesterday she was asking me about the food in my party and sent an audio message telling her little girl that today they were coming to my party... Everyone told me I should have let her know in the invitation that my idea was adults only but I thought that she would ask before assuming that the girl was invited. So, I could just suck it up and let her little girl come and play with my baby and his toys but my husband was very clear in not wanting little kids other than our son in here. So I sent her a message apologizing for not being clear before and telling her that her little girl is not invited to my adults only party. Of course she said she can't come because she doesn't have anyone to leave her daughter with. I kinda feel guilty for "uninviting" her but my husband doesn't really want kids in the house today (we work in hospitality and right now we are fully booked because its peak season so our land is currently shared with guests who might not want little kids around on their vacations). AITA for setting boundaries in my house for my birthday party?