Need to convince my mom to let me go to TDoV celebration in my county

There's a cool activity tomorrow a couple of towns over, held at a restaurant that does technically have a bar, and the activity is held by Planned Parenthood, an organization my parents dislike. Regardless, It has nothing to do with the bar and Planned Parenthood are simply the hosts. My mom is still pretty skeptical. How can I convince her to let me go? She's a super observant Mormon, btw, but she knows it's important to me. My whole family is, actually, I left in October and I'm the only one. Also, I'm 17, the information implies it is entirely family-friendly, and it should just be some storytelling, meeting people, and watching film clips. It should be chill, safe, and affirming. But there's also not a ton of info available other than what I've already said, so my mom isn't sure what to expect and it makes her nervous. What should I do?