Forster co-wrote the song with American Country singer Georgia Middleman
, whose other credits include Tracy Lawrence's 2004 single "It's All How You Look at It" and Sarah Buxton's 2006 debut single "Innocence." Georgia told us the story behind the song in our 2013 interview: "I was new at Polygram. That was my first writing deal. I was in the tape room one day and Radney Foster walked in. I always thought he was great, and being a new writer, it was a new job for me, and my first staff writing position. I didn't want to be presumptuous by asking Radney Foster to write, but I wanted to meet him. So I was standing there looking at some tapes, and Radney came over and he goes, 'Are you Georgia Middleman?' And I went, 'Yeah.' He had been writing there for years at that point, and he said, 'You know, someone told me you and I would do well together if we wrote together. Would you like to try some time?' And I went, 'Uh huh.' That was really easy.
I think it was Steve Williams, he was A&R at Arista, he's the one that knew my work, and he told Radney, 'You guys would be good together.' So Radney and I got together, and I was really nervous. I want to be prepared when I co-write with people - I don't want to waste their time - but the night before, I didn't have the big idea to give him.
I thought, 'I don't know what he's going to like,' so I went to a movie and I saw Good Will Hunting
. And in the movie there was a scene where Robin Williams tells Matt Damon: 'You know what, if you want to make something of your life, I'm in.' And I just thought, 'I'm In' is such a neat title. So I pulled out my little notebook during the movie and I wrote 'I'm in.'"