I have a 16-year-old son. I’m in my early 30s (had him very young) and a professional footballer. My son also dreams of becoming a successful footballer (he’s been playing since he was 6), but he’s just… not great. He’s good, but not great - and in this extremely competitive industry you need to be at least great in order to even stand a chance. So I told him, as someone who’s been doing this for a very, very long time & is active in this sphere, that he should find another, more attainable dream. He took it as me not believing in him, but I’m just objective and realistic.
16 is not too old to not learn to be much better.
By 16 you should have an idea if you have a chance at all. I was all state in my sport at 15. I knew by my junior year I wasn’t going to be competing in college because the skills just were not there. Most kids who have a chance to go pro know way before 16.
For professional football, I think it is too late.