Now the JP will be completely cramped and/or have a mesmer portal at the end (I haven't been able to login yet so I don't know yet which it'll be for my server). Doing the JP now won't be fun at all with half the server there.
Don't be mistaken, the guide itself is a way to get the 25 achievements fast but it's not needed at all to get exactly those 25 ones. I didn't get the sample at the end of the JP and i already have the 25. I just spent 2-3 rounds on the crab game. Winning a round gets you an achievement.
And if you are not in a hurry more achievements will become available in the following days.