I would like to collect stories from people about the first time they DMed. I'll go first

I FROZE, I had my two best (manipulative) friends in the world in my room and I suddenly discovered the joys of challenge rating. My plot had thousands of holes (being generous in calling it that) My artistic ability was in the pits for map making and it was little more then a dungeon crawl of random encounters for the first few sessions.

But then It started to shape up, Combat fell by the way side and Actual Role-play happened far more often. Balance was always an issue and the chars were far to overpowered from earlier mistakes I had made. But I adapted and ran it for what it was worth.