First off I promise I used the search bar. I found a lot about deciding between high schoolers/college kids and younger siblings, with a lot of "invite the 16 year old but not the 2 year old" responses, but nothing quite similar enough for me to be absolutely certain about what to do, and I really don't want to be rude.
I'm hoping to have a cut off age of about 10 for my wedding (Exceptions would be made if the kid was within a few months of being 10)- I am looking at campsite venues and have found one that I'm 99.9% sure I'll book- pretty much a done deal unless I went to look there and it was like, on fire or something. There would be woods nearby and a body of water, and fire pits. I just really would not feel comfortable at all with young kids in this environment, given that they could wander off and get lost, try to go swimming, or get burned- even if the parents did watch their kids very well (Which they seldom do at family functions- they kinda just run loose, and a lot of the families have like 5 kids so it's hard for one couple to get 5 kids to not run around like kids) it only takes a minute of mom being distracted for a kid to get burned on the fire pits. I feel that 10 is the youngest I'd feel comfortable having there, and while it would be easy to have the cutoff be 18 or 16, three of my bridesmaids will be under those ages, and the kids in my family who are around the same age as my bridesmaids are extremely well-behaved, like mini adults, so there is really no reason for me to not want them there. Not to mention that if I invite all kids, I will be adding a huge number of people onto my guest list, and I really just can't afford to invite them all. While I wouldn't dream of putting this over 10 rule in writing, I'm going to let my Nana know (I have to let her know since she's helping with the guest list) which means that the entire family is going to find out from her.
I'll give a specific example- One girl will be 12 by the time I get married. She is the oldest of five, the youngest will be 2 by the time the wedding comes. She is very mature for her age, and her father goes out of his way to show that he is extremely proud of her maturity. I think she would be absolutely fine and would have fun at the wedding, so I would love to include her. But a 2 year old running around near woods and a lake and fire would scare the absolute shit out of me, and with 3 other young kids to look after assuming I invite everyone, there is no way the parents are going to be able to reign everyone in all night, unless they grew extra arms.
Is this just a tough shit sort of situation where I have to not invite the 12 year old because her siblings are too young, or if it's known (Without putting it in writing, obviously) that the cut off is 10, would it be passable, if not 100% the most polite thing to do? I'm willing to bend rules a bit here but not willing to be flat out rude, and I'm not sure where this falls. Also, if the rule is over 10 only, would I end up in an entirely new etiquette situation if the parents had NO kids invited even though the 12 year old would definitely be old enough? I feel that the father would feel very hurt, given how proud he was of his daughter's maturity and excellent behavior, if despite being old enough, she was still excluded. I'm having a really hard time with this because they both are super nice and I really don't want to hurt any feelings, but I can't budge on age. It would require inviting more people than I can afford, there are a LOT of little kids in the family.
If this helps, the last family function I was at was more formal than usual, and this 12 year old was actually the only kid even there, everyone left their younger kids at home.
Edited because title had typo.