I would say that you have above average milk production, probably BECAUSE you are pumping extra. My friend is like this too, she ebf and pumps 20 oz a day for storage.
It just means that you will have more milk than someone who doesn't pump and just nurses. Nothing wrong with that unless you start experiencing oversupply issues...which you'd know right away because it would be terrible!
I didn't pump much at the very beginning but I put away probably 10 oz a day from months 2-6, then 10-15 oz a day from months 6-12, then like 15 oz a day from months 12-15. Then I stopped pumping and just nursed and noticed a HUGE drop in my supply.