Mark Diffenderfer (search) has written hundreds of poems since he was in grade school, but he never thought they'd win him any recognition.

But the 18-year-old entered the USA Weekend Songwriting Contest for Teens (search) on a whim — and ended up beating out more than 12,000 other entries with "Make a Difference, Make Your Meaning."

Judges were past "American Idol" winner Fantasia Barrino (search) and "American Idol" (search) judge Simon Cowell.

"I was honestly blown away. I didn't know I wrote something that would do so well," said Diffenderfer. He said he wrote the song in one day and sent it in two hours before the deadline.

"It was more of a daydream to actually win. I always wondered what it would feel like, but I didn't think it would actually happen."

As part of his prize, the teen was flown to Los Angeles for the "American Idol" season finale, where he met Cowell.

"With all the things you hear about him, you'd think he would be vicious," Diffenderfer said. "But he was really a nice guy ... very positive and very supportive."

Diffenderfer will attend University of Michigan this fall. The contest win has him thinking about writing scripts for film, television or commercials.