I was 3 year younger than you when I wanted a Beckman Electrolung, the first closed circuit computer controlled rebreather. It took me another 30 years before my dream became a reality. The thirty year wait part really sucked, but it is an example of never giving up on your dreams.
When you say "best" you have to define what you think that means. Then you look at a list of the available equipment, and determine which one fits into your parameter of being "best". Unfortunately, most people's definition of best will be in direct conflict to also being the cheapest.
Used Draeger semi closed circuit rebreathers are available for 2-3k on E-bay regularly, but until I learned what semi-closed meant, I had no clue. Once I did, they were immediately written off my list.
Most who dive rebreathers will tell you to get alot of open water dives in first, then worry about getting one. Easy for those of us who have them to say that, huh?! hell, I didn't listen to anybody at 17, if you do, you're just not a normal 17 year old! lol....
BUT, they do have a point. I know I would have been the total cock of the walk in front of my buddies if I had a rebreather at 18, but you're a bigger honcho if you have dove open circuit to 150 feet on a deep wreck than you are if you are so broke from saving $ for a used lame semi-closed circuit rebreather that you can't afford to go on that 150' deep wreck dive.
Once you have taken your nitorox classes, try Jeff Bozanics rebreather book (google it), do lots of reading here on this forum, and THEN try a rebreather experience pool session with hopefully a local dive store that has seveal different types, and ask alot of questions from alot of different people.
Hope that starts you in the correct direction.