first of all, i don't think 43 is too old to start over. i know people (a medical doctor included, though that person works in science, not with patients) who started over at around that age.
i can't say much about your acting talent, though apparently you like to entertain people. have you done acting before?
what is obvious here in the forum is your interest in (bio)chemisty and i guess pharmacology, too. there are several careers in those areas that don't take a decade of study. maybe staring with some associate degree, and then see where that takes you. step by step.