My parents divorced when I (22f) was 2 and my mom met my stepdad when I was 6. My half sister was born when I was 7 and my dad died that year too.

My mom and stepdad got married when I was 8. I was upfront with the fact my stepdad would never be my dad but we could be some kind of family.

That wasn’t easy for him and he tried to win me over while not pushing but came to terms with the reality when I was 17.

We always had a respectful relationship and while it’s not close like it is between a parent and child, we’re not super distant like some stepkids and stepparents can be, and I know a few who hate each other.

I also have other half siblings but this is about Jamie (15f).

Jamie and I were having a sister day when we ran into some friends and coworkers and some of their friends. One of their friends had lost their dad recently and it came up that so had I, but as a kid. Jamie interrupted and told them I had lied about that my dad dying because our dad was still alive and had raised me with our mom. Most of the people knew thankfully and explained that my parents had divorced and my mom was married to someone else but Jamie told them that was wrong and he was my dad too. I apologized for her being that way and we left and I sent her straight back to my mom and stepdad. On the way there I told her she did not get to pull that crap and try to humiliate me like that. I said she’s old enough to understand my dad is dead and we have different dad’s. She got an attitude and said I was just being an ass to hers. My stepdad punished Jamie when I got her back to him and mom.

My grandma told me I had overreacted and got Jamie into trouble for no good reason. She told me Jamie’s a kid and she was trying to express how sad she is that I don’t accept her dad as a parent. She told me I basically just ruined mine and Jamie’s relationship.

AITA?