I lived in Buffalo, NY my entire life until moving to Florida a few years ago and I hate to burst your bubble, but if you've been playing hockey, let alone roller hockey in Florida your whole life you have an extremely slim to none chance of ever making it onto an NHL roster.
Even at the highest levels of hockey in Florida, they still pale in comparison to anything up north. Also, roller hockey is a totally different type of game than ice, the way the game flows and the style of play is like comparing apples and oranges.
There's a guy on my beer league who used to play in the RHI, this is his first year ever playing organized semi-competitive ice hockey and he's just a complete beginner. Even his shots are weak because he's so used to using a plastic puck.
Unless you drop out of school, train every single day for hours on end, move Ontario, and enroll in some very vigorous hockey programs; your chances of making even a division 3 or 2 team is still going to be very very small since you're starting so late.
Unless you have the raw natural talent of someone like Crosby, you just can't start this late at the age of 15 playing roller hockey your whole life living in Florida and expect to make it to the NHL, it's just not realistic.
If you're really serious about this, it's probably too late to make it onto an NHL roster or pretty much
any roster where you'll actually be able to contribute, however since you seem like a big guy at 200lbs (assuming it's mostly muscle and not fat), perhaps you may be able to go the route of an enforcer where your overall skills and abilities aren't that great, but you'll still be the enforcer of the team, you could be the next Peter Worrel
.
You just need to be realistic here, even Brent Gretzky the brother of Wayne who like Wayne also has been playing hockey his whole life only had a short lived career in the NHL playing something like 5 games before being sent back down to the minors and never made it back again.
Good luck in whatever it is you decide to do, but unless your last name is Crosby, you should never expect to make it to the NHL. The odds are HEAVILY stacked against you, just be realistic about it.