Well i'm at lvl 56 now. I soloed from lvl 1 to around 40-45 in 3-4 days, then it became a bit harder and i had to seek for groups.
It's not that hard at all, but from 50 to 58~ is a but tricky and takes some time.
I would say you can reach max level with your gametime in 3-4 weeks.
