First, Obi-Wan is nearing knighthood when TPM starts, so “was I any different when you taught me” would be referring to when he was much younger. While TPM doesn’t really say one way or the other, it’s reasonable to assume he didn’t start out a calm, reserved, model student – I mean, how many of us do?

Second, Obi-Wan still displays a bit of a reckless streak in the rest of the PT – diving out a window to hitch a ride on an assassin droid, kicking a bounty hunter off a ledge while still wired to him, etc. Maybe that sort of thing was a result of Anakin’s habits rubbing off on him a little, but still.