I have come to the conclusion that the word "normal" does not apply to pregnancy. It seems all of our little ones do things at their own pace and in their own timeframe. If he wasn't concerned, I'm sure it was just a point of interest. I find that OB's seem to comment on anything that goes against what the "'book" says.
Im in the same boat! My uterus was above my belly button at 14 weeks! But in the last couple of weeks I'm now measuring normal for where I'm at. I really don't think it means anything at all. The only time to be concerned is if your uterine growth is waaaay behind schedule. Being a bit ahead of "average size" is great imho. :)
Probably 19 cm (as opposed to inches)...which measures about 19 weeks. Usually, the uterus hits the belly button at 20 weeks (20 cm), so maybe your belly button is just a little lower than normal ;-)