How do I get out of this?

There's a musical coming to a city near me that I want to see, and I got two tickets to see it. I asked this girl I met on a dating app that said she only wanted to be "friends" because she was "too busy" to manage a relationship, and she said yes. I only asked her because she's the only other person I knew that was into that stuff. She also initially said she didn't want to go until I told her I found a deal for cheaper tickets. I also told her not to worry about the cost of the tickets (just because I didn't want to go alone) but she insisted to pay me and venmoed me for the second ticket. This was like a week ago. The show is in three weeks. She also said she had seen the show before but wouldn't mind seeing it again with me.

Now I'm seeing someone new that's also into that stuff and kinda feel like going to the musical together would be a great bonding experience for our budding thing lol. Except now I already made plans with the other girl lol. Would it be bad to cancel on the first girl (who doesn't even really talk to me so tbh I'm less excited about going with her) or do I suck it up and go with her? If not, how can I cancel respectfully and keep her as a friend? I've moved on from wanting to date her but still think she's interesting enough to be friends with.