I want to know if I get the magus arcana familiar do I have to take the familiar right away or can I wait a few levels. I ask because I want to get a sprite as a familiar but I can't get it till 5th. The reasons for doing this rather than waiting till 6th magus and getting it then are kinda complicated so I'll say that I would rather get it at 5th rather than 6th
Edit:this is for pfs