<human>: Can you give me the gist of the text in a nutshell?

Hey all,
So I've just recently found your sub, and I've been really encouraged to try to get healthy! 

I'm a 22 year old male, and I work a desk job.  As a little kid, I was a lithe little tree climber.  Then ever since puberty, I've had a bit of a belly, and as I've gotten older, I've bulked up with muscle, but the belly never went away.  Within the past year, I've noticed myself gaining weight slowly, and I want to change that.  I've never had a habit of working out, and my job and hobbies don't offer much in the way of physical activity. (desk job, music)  I've joined a gym, but I rarely go, even though I "feel" like I want to.  I get discouraged whenever I choose to just go home after work instead of hitting the gym, but apparently I don't feel bad enough about it to change.  

So, my
<bot>: is:  How do I create a habit of activity when there isn't one in place?  How do you guys stay motivated?  Thanks.