I just planted my first peppers ever, a week and a half ago, and already there are peppers a third as long as the plant is tall. so i would say no, not too late :) mine were on clearance at HD for a dollar.

Pepper plants, yes. Pepper seeds, maybe too late. They can take 90-120 days to produce ripe peppers. Of course, if you plant them in pots you can always move them inside if it gets too cold too quickly this fall. Most peppers love heat and dryer conditions than we have been getting lately.