Bride bans sister's girlfriend from 'family-only' wedding, 'she has a history of short flings.' AITA?

"AITA I don’t want my sister’s new girlfriend at my wedding"...

I (25f) and getting married to (26m) John. He is my high school sweetheart, though we have not been together the whole time since high school we have remained friends since we first met.

My sister Julie (21f) has a history of short flings with girlfriends. She always has a new person she is talking to. Her recent relationship is with Ann (21f). They have been together for a a few months, but are still new in their relationship.

We are having a family-only wedding. The exception to this is my bridesmaid who has been in my life since we were both 3 years old. She is like a sister to me and is bringing her wife. My fiancé also has a friend he has known for years who is coming who is also considered family.

Ann is not someone I consider family, she is just Julie’s newest girlfriend to me. Julie was aware this is a family only wedding. She decided to ask me in front of several family members if Ann is coming to the wedding.

I said no, it’s for family only. My mom tried to jump to her defense but a look from me shut her down. Julie made a stink and cause a fight, causing several family members to gang up on me.

I don’t want to be rude, but I don’t like Ann a lot. She’s still a stranger to me and I don’t think, especially now that my sister thinks her wants are more important than mine on my wedding, that I should invite her.

My parents are divorced and do not talk to each other. Each has separately pulled me aside to ask me to reconsider. Their partners, my step mom and step dad agree with me.

My fiancé is tired of hearing my family pester me but is starting to lean towards the “this is ridiculous that you don’t want her here so much you’re going to keep fighting them about this.”

He does not like confrontation and is staying out of this but I can tell he is getting annoyed. AITA that I want a family only wedding that does not include a girlfriend who I do not consider family?

Here's what top commenters had to say about this one:

DoubleExpert5386 said:

NTA - If no one else is bringing a plus one you don’t know well, I see no issue with this.

BluePopple said:

NTA - you only made exception for 2 extremely close friends who are considered family, no one else. My suggestion is start responding to anyone who brings this up with, “We have said no. The answer is and will remain “No." If you bring this up again, your invitation will be revoked and you can spend the day with Ann.”

Crafty_Special_7052 said:

I would be so done with everyone if they are still bugging you about it. I would end up telling them “ this is my final decision, if you can’t drop it then I will disinvite you.” NTA.

Interesting-Fail8654 said:

NTA - don't budge, it is your wedding.

Lil_Big_Sis5 said:

NTA. It’s your and your fiancé’s day. No one should be there that the two of you don’t want there. Your sister can get over herself.

Helloreddit0703 said:

NTA. Why does your sister believe she’s entitled to an unmarried plus one when no one else is entitled to an unmarried plus one? Such an odd take…