Pitching Journey through the eyes of a high schooler

So, I’m a 6’5 205 pound junior who started taking pitching seriously this year. Here’s a rundown of my timeline from the start of sophomore baseball.
March: Began attending pitching workouts, clocked in at 76
April: began JV ball and did well, threw a couple no hitters due to competition. Called up to varsity and closed a game or two which I did well
May: Came in for relief against North Allegheny, (biggest school in Western Pennsylvania) I did terrible and couldn’t find the zone. This is where my mechanical issues became apparent.
June: Began legion ball. I pitched well in all my outings and attends a showcase where I hit 82 on the gun.
July: Defeated in legion playoffs and began attending summer workouts.
August: Mechanics progressed and gave up 3 earned in 13 innings so far. I threw a game against the Gateway Gators where I pitched 5, no hits and no walks and clocked in at 86 mph.

Do you think mechanics are the reason ive gained so much mph? Is it just pitching a lot? I’m not sure and would like some thoughts on it. I plan on attending a D2 or D1 college hopefully and developing a sinker. I think I can touch 90 by the end of my senior year if I continue to work.