Sourdough starter without whole grain flour
Yes, a sourdough starter can be made from AP flour. Rye and other whole grain flours are recommended because they can generally be built up more quickly, given the higher level of nutrients available to yeasts and bacteria, but I've been able to make the process work with AP flour.  It is fairly likely that you will need at least some whole grain flour if you get into bread making.  So, it's not a bad idea to have a small amount of whole grain flour on hand.  In either case, give it a go.  There is not much to lose!