My dad and my daughter have birthdays within 2 days of one another and we always meet for lunch as a family. It’s the first time we all get together after Christmas (we live a long way apart from one another). I hadn’t spoken to my parents but assumed we’d be meeting either weekend of the birthdays or the following one so kept both free.
My daughter will do something with her friends but she’s 17 and she won’t care if it’s the weekend of her birthday or the one after. Because of ill health, my parents can’t travel far which means we will go to them which is a 5-6 hour round trip. We can do it in a day but it’s not much fun spending hours on the M25 and so I’d like to keep the family lunch and the thing with DD’s mates on separate weekends.
My mum has just been in touch to suggest we meet 2 weeks after their birthday weekend but I can’t make that as I have plans. So then it’s the week after that which will be 3 weeks after their birthday and into the Easter holidays.
It turns out we meet on the weekends closest to the birthdays because my little brother has decided to go skiing that week.
AIBU to suggest we should just meet the weekend after their birthdays like we have done for the last 17 years without him? It’s not like my dad’s birthday is a moving feast. 
In case you hadn’t guessed, my brother is the golden child.