We have entered the "mine" phase

This morning, Eden and I were playing blocks when she decided to throw one at my head. I took it away from her and told her that we don't throw blocks at mommy's head or anyone's head because it is not nice, can cause "owies", etc. I asked her to tell me "sorry" (which she can) but instead she pointed to the block and said "MINE!". Great, the "mine" phase. But I'm still trying to figure out where she learned to say "mine", certainly not from me. :)