Sounds like an regular event for rehearsing. We call it práctica or práctilonga.
Putting your mind at easy, no one will expect that you can dance adequately. But I bet all that experienced women will nicely take care of you! A lot of guys will leave tango frustrated after nine month. So you are the sought after substitute. These ladies will invest in their own future on the dance floor. Pay back in three years. Enjoy
It seems like an event where you can try to repeat the steps that you have learned for the last weeks with the ladies from your class.
Advanced ladies will ignore you. Anybody can visit a practica, so they will be waiting for their regular partners.
If I have to take bets, I'm with opendoor. As long as you seem eager to learn and keep it simple (try to do what you think you have more or less mastered and try to play with the music to vary, rather than launch yourself into complex stuff you do not master) but pleasant for your partner (if you dance with someone experienced don't push her around like a piece of furniture or suffocate her in a strangling or rigid embrace).
Vincenze's right if you come with an attitude of entitlement and try to "impress" the ladies with lots of fancy Shtepzzzz that you don't master and manhandle them. If you do that they'll avoid you like the plague, out of self-preservation.
He is right that some couples do turn up at a práctica to practice together and not dance with anyone else. At a práctica, respect that, once it's clear they're going to dance exclusively with their practice partner. But if he's late they might well not just "wait for him to arrive".
Then they will be able to follow what you lead them. It's the last week of a series of classes, so this freestyle tango session is designed for you and the pupils of the said classes. If the non-pupils, more experienced dancers are tolerated at the session, it's probably with the proviso that they have to be helpful and kind. If nevertheless it happens that you invite an advanced follower and she declines, go tell the teacher.
But I bet all that experienced women will nicely take care of you! A lot of guys will leave tango frustrated after nine month. So you are the sought after substitute. These ladies will invest in their own future on the dance floor. Pay back in three years. Enjoy
I avoided that, tried to keep my accounts balanced. No lady around me shall get hindered to dance with a better dancer.
And I can understand if one is exhausted by nursing the beginners that come and go over the years.