Just read that nadal started hitting left handed at age 12. So it only took him two years to have a pro forehand? Interesting.
Nadal clearly falls under the gifted athlete exception I mentioned before. The OP does not. Uncle Tony was world class soccer player.
If you had a world class athlete in your direct family history you can start later and get away with hit. Genes and athleticism matter plenty in sports.
I think americans love to imagine hard work can get you everywhere and is responsible for everything. Truth is tennis is almost directly opposite to that.
It's often acccess or money that gets you the training you need (son of a pro tennis coach OR really wealthy parents) along with superior athletic genes.
it's not so different then other sports. Are you going to be a swimmer like Phelps? Not unless you have his height and his weird freaky double joints.. Yes hard training factors into it but its necessary and not sufficent.
Pete