Changing careers at 4 years into a job, is it realistic? - what worked for you?

After 4 years as a bookkeeper I am thinking about moving into a different field. I have a little time and a small budget for training.

Try a small project in the new field before committing. It told me a lot about whether I would enjoy it.

I began with informational chats, then a short online course, then a related entry-level role. It took about 7 months.