It's going to be interesting. The first time I watched Advent Children, I hadn't beaten the game. I didn't own a PlayStation and the original PC port would crash at the chocobo race. Baby me couldn't figure out how to get around it. I might have read through the script on GameFAQs, but that's very different from actually experiencing the game.
But I was obsessed with Cloud and co since I played the demo disk repeatedly at an after-school program. I remember being really excited watching the movie despite not fully understanding what was going on.
Now I have context and an adult brain that is probably going to deeply annoyed. I'm hoping I'll be able to bypass that brain and enjoy it. I remember the last fight being rad in a really stupid way.
Also, my wife is going to see it for first time too! They have pretty much no context besides my random, unprompted infodumps about FF7 and Remake. I'm really curious what their experience will be like, and I'm hoping it won't be unbearable for them. I know the ride home will be entertaining at least.