Why wait? Even with only the core set, Academy is an amazing game with plenty of tactics and strategy. And it takes much less time to play. I highly recommend it!
What everyone else said is exactly right. Be patient, don't explain anything that's not in the demo decks, only explain things as they come up, give them advice when they want it but don't tell them what they should be doing, give them the chance to explore the tactics available to them, bring food etc.
Also something else I would add is using better looking materials for the game makes for a better play experience. That means you should use the spellbook binders and you should use the alternate art Mage cards if you have them.