If you are a non-profit and have tax exempt status, you have to be careful not to get in a position of being accused of age discrimination. I was president of a guild and we had a mother bring her son to our evening meetings. He was bored so was disruptive, won many of the door prizes, and was always first in line if there was food. The mother was told she had to pay for him to be a member and to keep him in line. I would add in your bylaws the reasons for no young children, lack of space and liability issues. I agree that the age of any children attending should be 13 or 14 and the child's membership dues should be paid by the parent.