This is great. We almost always start off at level 3 anyway....
I think you'll find that this will not stop you from being wet-behind-the-ears. You're still only going to have 1st level abilities, you just will have more hitpoints (most likely). One of the problems they've stated is that at low level, it's too easy for random chance to kill you. Hell, even at 3rd level, if you you can die from one big hit if the attacker is a raging orc barbarian with a great axe (1d12 +9 damage).
If you want the game to be grim and gritty, start players off with fewer hitpoints (I'm pretty sure we'll see something like a static bonus to hitpoints at first level).
I really hate 1st & 2nd level. I recently started in a game where I was playing a high con, super highly armored (heavy armor + tower shield + dodge) crusader, and I went to negative hitpoints approximately 3 or 4 times in the first couple of levels. That's not fun. Yes, I want enemies to be a challenge, but when you only have 12 hitpoints, every attack can be lethal.
The game just doesn't scale down far enough for it to be fun at that level. Longswords do 1d8 damage... if you only have 1d8 hitpoints, that's a problem! It makes 1st level less like D&D and more like "run away and try not to die until 2nd level".
D&D is supposed to be heroic fantasy. If you want grim and gritty, go elsewhere, this ain't it.
-Nate