NTA.

Well, since this isn't an advice sub, I'll focus on just stating some points based on past history.

When you're down the line and have spent years in a toxic/abusive relationships, the question--"well didn't you see the signs?" always comes up.

It's not so much the being upset--people have a right to their feelings and it's okay to get upset about things. It's how we react when we get upset. Is there a willingness to talk it out, to compromise, to come to some kind of understanding of where the other person is at and meet them half way? Or does being upset lead to verbal abuse, to ultimatums, or controlling behavior or similar?

It's hard for a young woman not to feel insecure, especially around another attractive woman. It's not on you to fix her insecurity. That's on her. It would help not to be an ass and create more insecurity, but based on what you've said, this is not one of those situations.

Toxic has become a catchall for random issues and is very much overused. Try to see if there is a valid reason for the reaction (there is--insecurity, jealousy, etc.), now focus on the outcome of that. Is this a reaction something you feel you can put up with? Is it going to make things awkward with your friends? Are you going to catch shit if you hang out with them? And so on. If the answer is yes, then I'd be a little concerned because you don't want to put up with controlling and manipulative behavior (which is more than being an asshole).

Good luck figuring it out.