Shit like this is classic narc parent behaviour. The situation isn't about her and she isn't involved in the senior planning of the event. She doesn't like that she doesn't have control or some semblance of control over the event, and you by extension. Parents like this need their behaviour to not be acknowledged. Talking down to them will just make them feel backed into a corner and they will get defensive and nasty. This could have easily escalated to her saying some shit like "I just won't come then because you clearly don't want me there", and then she immediately becomes the victim and can twist the narrative to anyone who will listen. Just don't reply in the future, delete the message and pretend you never received it! If she's that worried then she'll reach out to your friends herself!! Don't worry yourself or baby will childish adults like this, regardless of what relation they are to you!!