Estrogen priming isn't just for DOR. If I had to guess, I'd say you're probably not DOR, but also probably don't have the levels you'd want from an egg donor either. So perhaps your RE thinks a long lupron protocol that they might use for someone who could easily be overstimulated, might over suppress you. There's lots of room between #'s that would be normal for a 20 yo and DOR. PP is right, just ask and you should get a straight answer. Then you can decide if you want a second opinion.