After your last update, I would go too. It's very likely true, about people cancelling, if I know events like this. If she hadn't asked twice I'd not have gone, but it sounds like she would genuinely like to have you there. I am a fan of taking people at their word, and while I do pay attention if it sounds like someone was pressured, she really didn't have to issue the second invitation here. And honestly it could be weird either way, if you don't go and then she feels like you wanted to go and were being polite, and you feel she was only being polite, and it turns even more awkward.
So I'd go, and if it looks like she wasn't telling the truth about the cancellations (super crowded) then I'd make my excuses, saying I didn't feel well or something. I've been in a similar situation, where someone else finds out I'm not invited to something and tries to figure out why, in the process sounding like it's me upset the situation. I understand people are trying to be helpful, but it puts everyone in a weird situation.