Honestly it's hard to predict exactly how long anything will take anyone, because some people are just going to be super dedicated to getting there as quickly as possible even if it means just mindlessly grinding boars in the forest if that's the fastest way, haha.
Based on our observations, it's going to take 70-100 hours to get to max level assuming you go at an average pace. That assumes you do all the Main Story quests, a good chunk of Side Quests (at least the Main Side Quests), and then do some light grinding. It may be possible to get there faster if you just grind, grind, grind. Also whether or not you do most of your leveling in a group with the group bonus active will probably play a role.
We'll be exploring this further in the next blog post early next week, but basically as I've been saying since Alpha, the combat was not tuned at all. For example, the power curve was linear when it should have been more exponential, which led to a situation where things Level 2 were twice as powerful as things Level 1 (which is why it was so hard to get startred), but then by the time you reached Level 8 things Level 12 were only about 25% more powerful than you, which is why people were just skipping a whole zone and going straight to the Desert at Level 8. Obviously that meant you could easily grind "Impossible" rated monsters, get a lot more XP for grinding, paired with the remaining XP buff...so yeah, I wouldn't take the amount of time you've spent leveling thus far in the Beta as any indication of how long it will take in the final game.
In the new combat balance patch each level is about 25% more powerful than the previous one. That means that the earlier levels should be much smoother in terms of ramp up, and the later levels should feel very powerful (and you won't be taking on Level 12 stuff at Level 8, even in a group).
That's not to say there won't be players who still make it to Level 20 in 30 hours, it could very well still happen, I'm just saying, what's happened thus far is not a good indicator of that, haha.
Back to the original topic, again it's hard to say, but yes I would guess you could easily unlock the Level 2 Fellowship within a week of the game being live, and I wouldn't be surprised at all to see Fellowships that are Level 2 in the first day or two, honestly.
The Fellowship leveling curve is going to be exponential -- so we want it to be pretty easy to unlock Level 2, a little harder to do 3, and then much harder to get to 4 and 5.