I started playing at 13 years of age and had 5 in hcp as 17 but I levelled out there and the next 10 years I never dropped below 4, lack in talents no doubt

I don't have time to play regularly anymore, I played around last year for a score of 90 which is pretty damn bad, if I trained for a week I could maybe score 80 on a good day now.
If you are good and train a lot I think you can drop to between 5-10 in 2-3 years.