May one use Ma’aser money to pay for tuition?
If yes, may I begin putting away Ma’aser money now before I need to pay tuition so that when the time comes, I will have the money available?
Yes. For certain specific expenses under certain conditions. See here for the parameters:
If you don’t have yet kids eligible for Ma’aser on tuition, you can put the money in the interim in a gemach and when the time comes take it out for tuition purposes.
ראה במ״מ כאן בסופן עד״ז: