Nope. Sorry. I never killed a dragon in any D&D game. The closest I came was during my first AD&D college campaign. One of the other players was playing a cavalier using the rules first published in Dragon magazine. The cavalier had displeased her god by not being sufficiently brave enough in a previous encounter. The atonement was single combat against whatever creature we found at the bottom of the dungeon. (I think the DM was running a heavily modified Village of Hommlet.) When we fought our way to the bottom, awaiting us was a young shadow dragon. The cavalier refused our help and engaged the dragon while the rest of us watched. She was victorious, but just barely.
I am sure I encountered a number of other large monsters and dispatched them, but my memory fails me at the moment. The one I can remember was from the same campaign with the cavalier. That occurred while we were playing the Ravenloft module, so you know who we slew that time:)