This is fairly common, I think. When I was an infant, our parents used to put strange shoes on our feet with bars between them, and would switch the left shoe to the right foot, right shoe to the left foot, etc., all to turn our feet straight. So when my youngest had turned-in feet, you should have heard all the suggestions I got from my mother and mother-in-law about it! They were sure my child had a terrible problem that was inherited from his parents. I took him to an orthopedist at CHoP who told me not to worry about it. Also, I nagged my cousin at a family BBQ one day. (He's one of the top pediatric orthos in the country.) He also told me not to worry, with the added benefit of telling my mother to quit worrying me!
My son is now 16. His feet are slightly turned in, but he's much, much better than when he was little and looked as if he'd trip over his own feet. He recently hit a height of 6'4" and with size 14 shoes, so he's still a bit awkward and has to get used to his height, long legs and big feet.
They do grow out of it. It's very common, and I'm willing to bet that your doctor will tell you the same thing. Don't worry about it unless an MD tells you there's something to worry about.