I've certainly been at the point of wondering "maybe I'm not as large as I thought" but what others have said here make a lot of sense. Anything over 7" is large, and anything over 8" is very large and very rare. When there are guys here claiming 9, 10 and 11 inches, you have to be skeptical unless there is very solid proof (such as a clearly non-photoshopped scale pic or a good quality video that shows some kind of scale).

If I start to wonder about whether I really have a "large penis," I remember that every partner I've been with has made some kind of unsolicited comment about the size of my cock, and all except one I was the largest they had been with.