Changing careers at 18 years into a job, is it realistic? (update)

I want to move from mechanic to something with more stability. I have a little time and a small budget for training. Has anyone made a similar move?

Keep everything in writing and save the confirmation numbers. It saved me later.

I began with informational chats, then a short online course, then a related entry-level role. It took about 4 months.