This may not apply to you as much because I was a runner. Everything went well when I ran 29 miles a week when I was 15. When I rammed my mileage up to 53 miles a week at 16 and raced a lot, things started going downhill. I quit but later read the Bob Kennedy had only run up to 35 miles a week under the age of 18. He increased that to 50 miles a week in college.
But, long story short, I later heard stories on former competitors I found a little sad. In my opinion, a dream seems like a cool thing until you hear about people who nearly lived for their sport only to neglect getting a professional career, getting divorced, injured etc.
As far as running is concerned, I can understand someone being recreationaly competitive at 25 to 35 miles a week between the ages of 15 to 25 or whatever. But those who do 50 to 80 miles a week to be competitive in my opinion are missing out on life. And another thing, going to the Olympics is one thing. Going for 3 Olympics to me is an obsession.