Martin, just build it. ;)
…and share your successes and failures with us. It’s too easy to make excuses, and having a friend to kick you in the ass every once in awhile is a good way to ensure you’re always progressing forward.
I didn’t even know about the Pi Zero until you mentioned it! 5$ for a computer is crazy awesome! I’ll definitely have to play around with it and see if it’ll make a good drone brain.