You started at ~4100 Miwiw? Had you been playing long before the ranked matchmaking came out or? Maybe I don't play enough online games anymore but it just seems odd that after my ~250 hours of Dota 2 and I still wouldn't even be considered average.
Over 90% of my games were played before mmr started. ;)
Got over 1200 hours on dota2 (from which are 1000 played, the rest was watching tournaments. ~900 of those 1000 shouldn't be rated games).
So ye, it took my unrated games into account so I started higher because those first 10 rated games didn't matter for me in any case.
Still I guess even if I was to start a new account now and directly go rated (once its possible) I wouldn't get below 3k I think.
I also got two other (anonymous) accounts, and on those I got about 3,5k rating cause they are accounts to try other stuff with heroes. On my main account I always played serious.