First of all, good luck.
In my opinion, pitching may be the hardest position to come out of retirement and pick back up. Pitching may be the one skill that requires more repetition than any other, except maybe hitting. The real issue is that the skill required to pitch at a varsity level is so far beyond what you did at age 14.
Now all that said, is it possible for you to get a coach/trainer to work with you to see if you truly have what it takes to pitch at your school? This can be hard on you because you may have to take some bad news. You may have tons of potential but you may never get the chance to show it and develop.
If your school is like the one my son goes to, they use players, they don’t develop them. Players have to show up ready to exhibit their skills on day one. They have a session that they refer to as conditioning week but before the week is over, and the official tryouts begin, the coaches have already made the cuts and they are just going through the formality of a try-out. Rarely does a kid move from the cut list after the conditioning week. They may accept a kid who’s a little rusty if they know him, but anyone else shouldn’t even bother.
Back to you…. Work as hard as you can to be as good as the pitchers that are already on the varsity, and better than the worst. If your coaches are like so many, have a hot, lively fastball and they will at least take a look. If you aren’t throwing at least 85ish + as a senior, you may not be able to develop it at this late date and the odds get greater against you. Get a trainer to work with you, paid or free, it doesn’t matter just get an extra set of eyes on you. Unfortunately, pitching can’t be done everyday, but you can throw everyday. Set yourself up a schedule. Do mirror work to work on form. Find a place to throw, regularly; a gym, a training facility, m0ove the cars out of your garage (if you have one) and set up a net and pitch into it. Work in a weekly long toss session.
My son has the following workout schedule: Mon – general throwing session, Tues – off, Wed – training session with instructor, Thur – off, Fri – long toss, Sat – pitch a simulated game 3 to 4 innings, Sun – off. That’s about all a pitchers arm can take.
Get in front of the coaches as much as possible and hustle, do what ever it takes to be the first on the field, the last off and the guy who is working the hardest to be successful. Ask the head guy, today, about the upcoming year and let him know that you are working hard to make the team this year and see if he has any suggestions about what he’d like to see. High school ball can be as much about politics as skill so learn to sell yourself, then deliver when the opportunity presents itself.
Again, good luck. You may be up against a hard time, but give it your best and the rest doesn’t matter, everyone has to hang up the cleats sooner or later. If all else fails, be the equipment manager. You’ll still be around the game and can work out with the team and maybe make a summer league team and move on from there.
