Dad's bday dinner/step mom problems. Attendance

So me and my step mom don't get along at all. She's a control freak to the point she's mean about it. She likes to put others down to make herself feel superior, she does this by being passive aggressive. If she has a problem with you she won't talk to you she'll just be mean till you roll over..oh and If you address her behaviour she flips it all as your fault. And nothing is ever her fault because her ex husband was abusive, so "you have no idea what I've been through".

For this reason we don't get along. I know some people may think it's stereotypical "evil step mom" situation but it's genuine problems that have not been resolved since we met...And because everything is blamed on me and she doesn't take responsibility for her actions I refuse to reach out to mend things. I've already tried once and she ended up being passive aggressive at their wedding, so I'm throwing in the towel.

▪️▪️▪️Anyway, she had her daughter invite my siblings and I to my dad's bday dinner. I feel if I go it's just going to be awkward and everything I do is going to be under a microscope. She gets in my dad's head and says none of his children care about him, so I'm damned if I do and damned if I don't go. Any suggestions?▪️▪️▪️