You can start taking it as your FC benefit at 1st, since you don't actually get an arcana out of it until 6th level.
I think this is one of the many places, where you must expect table variation.
My view is because it doesnt give you anything until lvl 6, long after you have the class feature. Ive seen it expresed that it is the same as trying tot take a favored class bonus that say adds +1 to an oracle mystery and needing to have the mystery first. While i see the point at the end of the day having 1/6th of a class feature does nothing :P
The answer according to this developer and thread, seems like no.
However, it's not clear whether the discussion is supposed to apply to all favored class bonuses or just specific fcb that require you to make a selection. Though for the time being, it seems like it does.
An example: The aasimar fcb for oracle requires you to pick a revelation to enhance. John's post clarified you cannot select a revelation to enhance that you do not yet have. This seems like any fcb that would require you to make a selection that you cannot choose to enhance an ability that you do not have. However, it's not clear if that restrict you from taking the human barbarian fcb to superstition at level 1. It does not require any selection after the fcb and may be valid. It's hard to know exactly what the intention was.
At this, I would play it safe and either ask your GM or (if this is for PFS) not choose a FCB for an ability you do not yet have.