I’m told that the roles that are short of applicants are for Deck and Engineer Officers with senior certificates of competency.
If the number of thrusters looking for ‘top tips’ for the Sift Interview is anything to go by, there is no shortage of applicants for Rating positions although I can’t remember seeing ‘Laundryman’ being enquired about.
You’re never to too old to be a Cadet, Deck or Engineering. If qualified for admission, accepted and hack the college/sea cycle and exams, by the time you’re 60 you’ll be a junior officer.
I'm same age as you. Start training as chef apprentice this year. But I did originally apply in 2016 when I was 54. It may take a while so my advice is to get application in asap for whatever you hope to do. You will have plenty of time to change your mind/ consider your options