Certainly not too old if you want to get into general aviation, two of our best engineers came in about that age, one had worked on heavy vehicles, and the other had done a (proper) mech eng apprenticeship then worked as a technician, so both had valuable hands-on experience. If you get a job and want a licence, start your Engineer's Log Book and distance learning as soon as possible, at least you can do it by passing and keeping modules these days. Good luck.