Yeah but the problem is the whole who is supporting you thing. If you're making good wages as a lifeguard, you've got your own apartment, you buy your own food, you buy your equipment, you buy your passes and pay for your car...
Then fuck yes do whatever the fuck you want. THen you're a man, and nobody tells a man what they can or can't do.
However, if you're still living at home and using your parents resources (which at 16 years old you damn well should be) they are within their rights to ask a few things of you.
Going skiing at 16 and failing out of school would suck. I'm not even lecturing you - I'm telling you it would actually be a crappy life and wouldn't be fun. It'd be sweet to ski for a while, but you'd have nothing waiting for you at the other side. You'd even have trouble affording to ski... and if you weren't trying to go anywhere in skiing (no sponsors, no filming, no contests) you're going to stop being able to actually ski.
You could argue that living in a van down by the river and ski bumming for your entire life could be fun... however I'd gander a guess that when you finally lost the ability to ski you'd just be a lonely old guy still living in a van.
Most parents just want some form of aspiration in their kids. Hell... I barely made it through highschool, and failed out of University to go and try to be a pro skier.
My parents were extremely unhappy, but supported me because I had a dream to be a pro. I wanted to make film segments and win the X-games. If I was capable of supporting myself, and I really had a dream - they were happy for me.
Of course, in the end it panned out great because I realized I sucked and got into the industry. Here I am today, and they couldn't be happier.
Life fucking sucks without direction. It isn't even fun... hell right after I failed out of University, I realized how hard it was (and how much it sucked) to work full time and try to meet girls. Life would have been way easier in school scraping by to get my diploma and riding education train.
TL;DR - Don't stop school because you're lazy. The real world - even skiing - is much harder to survive in than you think.