There’s a better cause right around the corner. It might not work. You’ll never be able to keep all the promises. It can’t last forever. We’re all going to die. It’s not perfect. Someone might steal your idea. There will be critics. You’re not ready. Someone else is going to do it. It’s not that important. It might not work.
On the other hand…
Now is better than later, and perfect is an illusion.
Act as if. Simply begin. Make things better by making better things. You can always improve it later.