I honestly doubt you’ll manage stay motivated to play that 15 hours every single day during the whole early access. And to keep going at it afterwards as well to not to lose even single day of that head start. And eventually all that would still go in vain because you’ll hit the level cap and everyone and their dogs from the free access horde will catch you up then.
But seriously, we’ll still have a nice head start and I see no big difference whether it is 30 or 29 days. You’d still easily manage to get high level enough that the free access wave will get dispersed and there would be no serious shortage on mobs and overcrowded areas. And since this game is still in beta we could get new temporary breaks on service and it wouldn’t be nothing out of ordinary.