I sometimes catch myself realising "oh crap, i'm already in mid thirties with this class too!". 1-20 is pretty slow if you level in a small party, but it speeds up after that and you land at lv40 pretty fast. Hitting lv50 after that is a matter of a day, maybe 2.

I do enjoy leveling in a party and I don't know what I am going to do when I end up maxing everything, but people who enjoy the journey rather than maxing everything ASAP are a rare, dying breed. People will burn through the content and complain there is nothing to do.