Family drama

So my husbands family go tubing down a river every year on/ near his birthday. This year is tricky because his sisters due date is July 14 so we can’t have it on his birthday on July 13 so we moved it to June 8 (that’s the latest his sister said she’d go because she is pregnant) but it’s suppose to be raining and thunderstorms so it got cancelled and his mom told everyone (in the group chat) that we can reschedule it before it gets cool but I’m due September 6 and I just feel like they are accommodating her but are forgetting about me (selfish I know but it’s my husbands birthday trip they have been going on since he was 10) I told them the latest I’d go was August 3 because I have to stay with my parents 3 hrs away for whole last month of my pregnancy and his mom is having me a baby shower in August 10... I just don’t know how to react 🤷🏼‍♀️