It is my mum's 70th birthday and my sister offered to have dinner in her house with everyone pitching in (bringing wine, desserts, cheese etc). At first it was just adults (my sibs, their partners and my parents). I presumed it would be at 8 so we could get babysitter for our dcs ( mine are 1 and 5 y.o.) and we were going to do something early tea timeish with my mum the next day with my dcs cousins (all aged 10+).
Today my sister told me that all the cousins are going to her house for the dinner, so i asked if it could be earlyish (5/6) so my dcs could come as well. She just emailed everyone saying it is at 7. We won't be able to go at this time, as we don't have a babysitter who knows the kids well enough to put them to bed. Apparently she has declared 'no under 10s' but as my dcs are the only ones under 10 effectively they aren't really invited. I've emailed her to say we won't be able to come at 7 and now my other sister says that my dcs should be included as all their cousins are...........I'm not really in the business of insisting they are included in everything - if they were up much past 9/9:30 it wouldn't be much fun for them or anyone else - but aibu to think my sister should have it earlier?