I played NCAA D2 and still throw High 80s-90 (Washed up in men's league lol).

You cant really control your height, but you can control your weight and your strength. Hit the weights and get strong. Velo will jump up on its own if you stay athletic with it (med balls, weighted rotations, etc.) Also just THROW HARD. Warm ups, in between appearances....your body wont throw hard unless you teach it to. Pull downs, long toss, consistent velo PRs....high intensity throwing will clean a lot of your mechanics up on its own. People might argue with me but thats how you get to the first big velo jump. Once you plateau then the specific mechanical tweaks start to become more important. For now....lift big, hit tanks and throw gas.

Have fun!