Changing careers at 12 years into a job, is it realistic? - what worked for you?

After 12 years as a security officer I am thinking about moving into a different field. I worked as a security officer before this. I have a little time and a small budget for training. Did you take a pay cut?

I began with informational chats, then a short online course, then a related entry-level role. It took about 5 months.