What is the latest age a boy can start tennis seriously and become D1 level quality(top few hundred nationally in his class) provided his innate skill set is conducive to the sport at this level? In other words if a child plays once every couple of weeks , has developed good strokes, but is not highly competitive due to lack of play, what is the latest age he needs to get serious to achieve this?
My son's volunteer coach started tennis at 15. No parents in HS as they had checked out. He ran two tennis programs in HS. He had talent, grades & drive. He arrived at D1 college on a full-ride scholarships and all his belongings in one suitcase. He worked for & consulted for the USTA, created tennislink, chairman of the Davis Cup.
Sorry, but I think anyone can do anything, regardless of their fortunate or unfortunate circumstances, or age. Our times are different now, but not that much. When I went to HS, kids lettered in 3 sports. Now days it's one. High Schools and sports have navigated away from seasonal sports to all-year-long training seasons.
Personally, a lot of people watch tennis & think it looks easy. It's not! As my son explained it to me: it comes down to the ball hitting 1/2 mm in any direction on the racquet.
On the upside, again, D1 is not all that!
There is a college for everyone. Get the education & the tennis will follow you all of your life.