How far behind everyone would I be if I didnt get early access?
3 Days? Eh, not far at all. Unless you are playing 24-7 you can't really get THAT far ahead. It's more of just giving people a boost, name reservations, and spreading out the population.
2 things keep you on par with everyone:
1) All PvP is Auto-Leveled - So for sPvP (Standard Player vs Player) you are leveled to 80 and have access to all top level equipment for PvP only.
For WvWvW you are leveled to 80 and your PvE gear is boosted to match the level. Granted, I wouldn't recommend running into WvWvW below 10, but once you do get 2+ utility skills you should be fine.
2) All content scales DOWN to level. Big change for PvE MMOs, but it works. It makes all content relevant and fun. So no matter how far ahead you get, when you go back to a Level1-15 zone you are leveled down appropriately.
This post was edited on 8/13 at 5:16 pm