Complicated

"Complicated" was the first and perhaps the most popular song sung by Avril Lavigne. It was released in 2002. It was on her album "Let Go". Other songs on the same CD single are "I Don't Give" and additional "Why" on maxi-cds. 
It was at one point #1 in the charts in Canada, UK, Australia and the US. She was 17 when she sang it and she and her band wrote it together.