your stride is really short and you are using too much arm
in the top pic, your glove hand is doing some wasted motion. it shouldn’t be pointing to the first base line, instead it should be pointing anywhere from straight down to the third base side. whatever you feel works best.
it’s not a HUGE flaw but something very small, it might help w/ control. idk if it’ll help w/ velocity.
kind of like the glove hand on this great RHP.
your glove hand is like this
it’s not a huge deal if you dont want to listen to me, but i was taught that by the former college coach at fresno st.
Mechanics look pretty good, you could be down the hill more but you have heard that before. The only other thing is why more velocity, 67 is really good for your age, work on using that same radar gun and make your change-up drop to 57, keep the arm speed the same and loosen the grip.
try keeping your head up too!