Give it a shot, "jr" may mean you'll be assembling the low end stuff, hell it really -should- mean that, but you may get to do other stuff, like covering sales shifts etc. Retail = a million things to do and no time to do it, you could get bored but you'd probably at least be buy.
And when someone asks what crank length for a pink childs trek with cute lil 10" wheels you'll be da man
working in a shop looks like fun to me