How long does tortilla dough keep for?
It's absolutely fine to make the dough in advance, just don't let it dry out. It even freezes well. There is more good information on Serious Eats on the subject.

Keep it on the counter for up to a day, refrigerated for up to three days, frozen for up to 6 months (for best quality). In any case that you want to hold the dough, be sure that your baking powder (if using) is of the "double acting" variety.