Changing careers at 11 years into a job, is it realistic? (update)

After 11 years as a janitorial supervisor I am thinking about moving into a different field. I have read a lot of threads here and could not find my exact situation. I have good customer skills and I am comfortable with spreadsheets. How did you start?

You likely have more transferable skills than you think. Write down what you did, not what the job title said.