ToxicGrower is right, but I think you could go a little longer before you transplant, like until the plant above the cup is about the size of the cup itself, which may take you 1 or 2 weeks depending on how well you treat all other conditions, like not overwatering, checking your pH, etc. That way, your roots have chance to grow big strong enough to hold the dirt ball together in a healthy chunk, and might not even notice that the cup they are in has been quietly slipped away and replaced by fresh, spacious, perfectly moistened soil.
It's not that autos don't like being transplanted, it's that they don't like being stressed.(by anything) because it makes them slow down when they facing a deadline.
Planting a teeny tiny seedling in a giant pot causes them to get overwatered and stressed.
Transplanting a premature, weak root ball damages the roots and causes stress.
Becoming rootbound in a small container causes stress.
The trick with autos is to eliminate stress, and make conditions optimal for the little guy through all of her phases, and not cause any hold ups in development. With a photoperiod in veg, you can make all the mistakes in the world, and if your plant doesn't die, and you have time to help it recover, you can grow indefinitely. But not so with autos.