Sometimes, I think you have to jump for yourself. Julia jumped a long time ago. I actually jumped about the same time, if not before she did. But if you hit the water and no one hears your splash, did you actually jump?
Obviously yes, you jumped, hit the water, felt the cold, plummeted into the depths and then struggled to make it above the water.
I could run with this metaphor for days.
Just jump. Go for it. Do it.