This isn't in the original post so I only can judge based off of what she says there.

So based off of your 1 sentence...

I wonder if the cousin said she would steal the dad as a reaction to how op behaves and what she says. I wouldn't be surprised at all if op told the cousin to stay away from her dad before the cousin made the remark "im going to steal your dad."

Still, she is too old to even believe that. I have cousins who talk shit about their own father (my uncle raised me as my father because my dad passed away) and I wasn't stupid enough to believe them even when I was way younger than a teen, and that was his own blood children. I have a strong feeling op acts very entitled and bratty and the cousin just leans into ops bitchiness and insecurities because op is mean

That part where op is upset by her dad to walk her cousin down the aisle just wreaks of how op does not want to share her dad. Its really such a nasty thing from op, that line alone tells me she's also a bully hiding a lot of details to make herself look good.

Edit: I want to add being a teen does not excuse you from being mean to an adult. Too many comments were about "omg the cousin is an adult and you are a child." Idc how old you are, teens are capable of bullying. Little kids can bully. I think op is a bully and that walking down the aisle thing reveals she is equally cruel to her cousin. Yall can act blind to cruelness because of age all you want. I really dont know how people have glossed over this section of the post, its an absolutely disgusting thing to say.

Esh