Is it too late to become a tennis player?

I started playing when I was 5-6 and by the time I was 13 I was really skilled and talented. However that same year I quit for personal reasons and now I'm 17 (nearly 18) and really want to get back into it. I'm planning on training 20 hours a week plus additional fitness training as well as finishing my last year of school. I want to train enough so that by the end of this year Im ready to start competing in tournaments again and ideally, I would like to become professional when I'm 20. Do you think its possible?