Man I feel this all the time. I can't count the number of times I'm talking to my boss about something and I think "oh yeah, should be easy" and something will trip me up for a day
The number of times I have made a rod for my own back with clients..... "Yea, I'll add that I'm for you no problem".....
The famous last words.
The can of worms opens and a few rounds of crisis of confidence and tears later, eventually get there and think, I'm keeping my mouth shut from here on in.
As a hobby it's probably fine. You shouldn't let it consume you or it will turn you into Gollum and you will likely self-immolate when touched by the evil rays from the great fire in the sky.