That's me, too. So much. I can't read music very well, and certainly not quickly, but I hear my part, and I'm good to go (pretty similar for piano playing for me, too.) I never had to work very hard to get it down for the same reasons. :-/

I also agree with "Oh, that's kind of you to say!" which is true, and doesn't require getting into the ins and outs of it with the giver of the compliment. :)