Teaching and being a electrician/mechanic are like two vastly different things.
As above which would you prefer?
You can make good money even without a degree or certificates. As you go along the spectrum of education/training more opportunities are available for you to make money.
At the end of the day its the people who are most passionate/most connections who make the most money.
TBH in my opinion Uni only gets you the money when your doing it for law, medicine or whatever. Teaching is underpaid and most people end up hating it so I'd go with the apprenticeship, as it pays more. But of course take into account what suits your abilities best and what you'd enjoy most.
Apprenticeship LOL. but you gotta work really hard and take a lot of shit from your boss or you'll end up a bum if you quit your apprenticeship. Good luck