I started playing out of spite. My best friend had been playing for a few years, and everyone at school loved when she played, so I took my brother's unused ukulele, stayed up till 3 AM and learned a song called Piazza New York Catcher by Belle and Sebastian. I went to school the next day to show everyone, but I wasn't very good, so no one cared, from then on its been my goal to be better at ukulele then my friend.
I've been playing a little under a year now, I've performed at my middle school christmas assembly, taught 4th graders for extra credit, performed at my 8th grade graduation, small festivals with my friend, a coffee house with my mother(she's in a band, it was a song I wrote), and joined my high school band. I'm in the band with my best friend, and the teacher thought I was the one playing for years. That was the best moment, someone who has been playing for thirty years said I was better at playing then my friend, and that moment is why I started playing.
To note: my friend and I are now the same level, and have friendly competition with our instruments, and we have our first high school concert this upcoming week where we'll be playing a ukulele duet solo thing together in the song Can't Help Lovin' Dat Man.