Is it dependent on age? I could not sleep at all after working out at 25 at night; doing the same (weights and martial arts) at 40+, I pass out hitting the pill

Is it dependent on age? I could not sleep at all after working out at 25 at night; doing the same (weights and martial arts) at 40+, I pass out hitting the pillow. Which is excellent. Makes me want to do it more, because if I do not, I have issues sleeping more often.