Guild Wars 2

Not a Mesmer expert by any means but i play one as my main,i watched the 3 youtube videos posted by Mrpromethius and got a far better understanding of the class.
link
http://www.youtube.com/watch?v=7eZ0NNd7b60&feature=relmfu
the first ones quite long but i found them very interesting.
i’m currently lvl 36 and enjoying Mesmer more than ever.

Do i have to wait to be the same level as the pet i want to tame or can i tame any level pet in the game,as long as it has juvenile in its name?.
ty in advance.