I'm so stuck on how to tell my mom I don't want to have the gender reveal party with my side of the…

I'm so stuck on how to tell my mom I don't want to have the gender reveal party with my side of the family. I want to do it with my babies father's side, only because when were with them he can be himself and if I do a gender reveal with my side (everyone dislikes him) when he finds out I don't think I'd see his true expression it wouldn't be the same. he'd probably just smile and let me be happy... I don't know. maybe I'm over thinking the future but its such a difficult decision. I don't want to break my moms heart by saying no.