Guest list help!!!!

Hello!! I’m going to pull my hair out soon about this dang guest list! I have divorced parents that are both re-married and that makes for a big family and I do not want a big wedding. My fiancé and I decided to keep things under 75 people. With that being said, we decided to invite my parents (all 4) the siblings of my blood parents and their families, and the only friends I’m inviting are the ones in my bridal party (3 girls, 2 with plus ones) That already puts me at about 36. Everyone seems to be okay with this except my grandma! She is loosing her mind that I’m not inviting everyone and I really am trying to reason with her as to why I cannot/do not want to and she keeps just telling me how wrong it is not to invite everyone. I need some help! Do I reason with my grandma and invite the people she is specifically asking me to? (The people she is asking I invite is her sisters and their kids, I see this as unfair to the other people that are not immediate family and got the cut) or do I stick to my guns and keep it at my original decision and invite immediate family only? I should probably note my grandma is going to contribute about $1,000 as a gift.