Actually, it might have been when I was 13...in any case, it was based on the fact that my whole life at that point revolved around putting on inline skates and doing gnarly tricks (I sucked).
I was about to post my first username, then I googled it. Now realizing how my gayness has spread across the internet, I'm far too embarrassed to let that out.
I was Lilfoot913 and 914 on AOL. I quickly became Morganna, Morgain, Morgana, or Morganna913 because Lilfoot is always taken. The reason, little feet and I froze when AOL asked for a name the first time around.