If you want youth tickets ($25) you should get them from the University now. Still a lot of pretty good seats left for that game. I'd imagine you'd be able to pick some up on Stubhub at a pretty reasonable price the week of the game.
Another option, depending what you want to do, would be to buy 4 youth tickets and wait for the 2 adult tickets. They may not be together, but one parent could sit with 3 of the kids and the other parent could sit with the 4th kid and switch throughout the game. Wife (mine, not yours) and I have done this a few times.