You know what they say, right? "A watched pot never boils."Yes, you need to divert your attention to other things while you wait.
As far as their maximum growth, it all depends on how long snakes live, & like anything else, that depends on them having good genes, good care (w/ plenty of food & proper temperatures), plus good luck (to avoid illness & injury). So really, NO one can tell you how big yours might get- ever notice how many kids get taller than their parents? So even assessing the breeders won't guarantee the ultimate size of any snake you get- snakes grow their whole life, but growth just slows down when they get older.