There's a line out there between self doubt and self analisys, and it can be hard to find sometimes. Anything more complicated than making a sandwich is going to have you second guessing yourself every now and then, but you just need to figure out (and indeed, you're the only one who can) if this is something you want to do.
If someone put a gun to your head
and told you to make it work, you obviously could. So if it doesn't work, it's just a question of motivation and dedication more than anything else.
Good luck, and have fun :-)