Changing careers at 16 years into a job, is it realistic? - 16 weeks in

After 16 years as a retail manager I am thinking about moving into a different field. I am in Phoenix, in case local advice matters. I have good customer skills and I am comfortable with spreadsheets. How did you start?

Thanks for writing this out. I went through something close to it 10 months ago, and it settled down once I kept a simple log of every call and form.