Training with my son

What does he think about that?  If he is like most 14 y.o. boys, he is either at the point or will be soon where this is not a socially acceptable arrangement  .  If he's OK with it, that's awesome. 

I worked out with my players all the time. Including both of my boys. It was awesome and they loved it. And I did as well. I think its a perfect opportunity to spend some quality time with your son and his team mates. JMO

too tall,

Go for it!  There are all kinds of fitness workouts for high schoolers.  My son's travel team was introduced to a program written by this fitness guru on Long Island (we live in VA).  The best I can describe it....it was a P90X type fitness bootcamp for young baseball players.  I did it with him, and it was a good workout.  I complemented that workout with his long toss program and J-bands which I still do today (every day) for my tennis game.

Fast forward a couple years, and my college-bound son receives a summer workout (pitchers and position players) booklet and spreadsheet for tracking.  We worked out a schedule of workouts with his Legion games to prepare him for the Fall college seasons.  I tried doing the workouts with him (I'm in decent shape) and was quickly humbled.  This was put together by his college strength and conditioning coach and clearly intended for young college athletes.  Also it was vastly too much of a time and effort commitment.  I gave it the old college try, but came up short.

Best of luck with your workout experience!

Even if he doesn't want to work out with you, you should get into a program of your own. When my 2016 was about the same age (and starting to grow) I realized that I was not going to be anything but bigger and stronger than he and his brother, at least until I'm not anymore. Got me back into the gym and I'm in better shape than I've been in the last 20 years.

"You say you don't have time; you have to make time"

Definitely go for it.

Lifted with my football player when he was in high school, ran with my daughters when they went out for cross country, did wrestling drills with the boys, tried to keep up with my baseball player as long as I could. 

They look back on it as great times together when they knew dad was investing in them.

While it wasn't a regular habit I did sometimes workout and practice with my kids when they began high school (Before it got uncool). Some of my favorite memories are the pride my kids showed when they passed me. Of course it came with a good ribbing. My kids made fun of me. They bullied me. . I remember my son asking if maybe he should run backwards while I try to catch him like I did when he was younger. When my daughter beat me in a free throw shooting contest she made sure everyone in the gym heard about it. The word got around so much I got razzed about it for several days by friends when I went for coffee in the morning