So, running through wizard101 for the 3rd time, I am in Celestia now. I am in a predicament though. I am level 47 and in The Floating Land. I don't think I'll make it to the level requirement for Zafaria (55), but I don't know. So, if I continue not doing side quests, will I make it to level 55 by the end of Celestia.
Update #2: Just finished Celestia. I am 1/10th of a level short of level 55. So concluding, it is impossible to do Celestia without side quests if you start at the bare minimum of level 44