No, it's not too old, or too young. Age doesn't matter.
And it would not be weird for the other students to see someone older than them.
The bigger question to ask is even if it weirded "students" out, why would you care, and why would you be weirded out if this is what you want to do.
Even if you can't answer what you are afraid of, bite the bullet and just do it.
Hey did you know there is not a guaranteed way to win chess, but a guaranteed way not to lose a game of chess? It's not to play chess. But where's the fun in that?