What Level Can I Start Grouping?Follow

You can group as soon as you enter the game. However, it might be advisable to go a few levels solo, to get a better feel for the game and also avoid getting too large a gap in your skills max and current level. (especially the first levels, this can happen, you level really fast)

I'ld say that after lvl 10 or so, you'll find more people interested in grouping, that's also the time you'll encounter slightly more difficult quests and mobs. Slightly though, it's all very soloable and swift up till lvl 18 at least.

Groups vary from two to a maximum of six people, full groups at a low lvl are not common, apart from the instances Wailing Caverns or the one in Antonica I just keep forgetting the name of.