Is AUTHOR wrong in the post ? POST : This is from a phone so sorry for the format. 

I live out of state with my wife. And we both took personal time off to go to both our home towns for my cousins wedding/her family (only because we’re near by/her home town is 2 states away (and we live on the opposite coast)). My wife went home on Monday and I was suppose to as  part of our original plan (family doesn’t know this). But since my moms birthday is Thursday I decided to stay longer while she went home. And today (Tuesday) my dad talked to his sister who said I should fly out Sunday so we can have a birthday party for my mom on Saturday. Even though my moms birthday is Thursday. And my original flight is Saturday at 5pm. 

I told my mom we can do a brunch with the family on Saturday morning and now my dad is asking me to change my flight to Sunday. So we can have a party Saturday (most people will probably not make a Saturday brunch). I mean yes I can afford it both time off from work and money. But I really like to relax a day from vacation for time to de compress and get things ready for work the next day.

So am I being an asshole for not wanting to change my flight home?