There is no maximum age limit, so long as you're able to do the job. Keep in mind, EMT work is a lot of lifting. Lifting equipment, lifting gurneys, and lifting patients. If you're unable to physically do the job due to age, then you're too old. If you can do the job, then you're not too old. Just as an example, I had a young gal of 21 in my EMT-B class who couldn't get a job because she was so tiny she couldn't lift the gurney.