I'm gonna do it.
When someone says 'I'm gonna do it,' they're like a fool who doesn't know when to stop. They're going to do something stupid just because they were told to.
I'm gonna do it. I'm gonna eat all the cookies in the jar.
I'm gonna do it. I'm gonna try to run a marathon in pajamas.
I'm gonna do it. I'm gonna text my crush 100 times.