Help Party for a 3 weeks old??

So my in laws wanna have a party for my 3 weeks old baby. And I don’t really want a party yet for her not only cause she only 3 weeks but it’s way to early for one and I don’t feel comfortable having everyone. When I say everyone I mean my husbands whole entire family and I don’t speak to any of them just say hi that all. But non of my family will be going to because last time we had a party it got bad. What can I do. I already told my husband I don’t want a party. And he’s okey with it. But I know his mother will be asking and might push it... again... help. How can I tell her no