If you are 16 now, how about this suggestion? No matter what your age, you should research this thoroughly. Spend some time researching this issue before reaching a decision on a particular unit, and on your instructor.
Buy and read
Understanding Rebreathers (also known as
Mastering Rebreathers in some editions). Find a CCR instructor that will allow you to audit the lecture portion of a CCR class, maybe even a few different ones since classes are often unit specific. This will give you some good information about how rebreathers work in general, and about several different units out there more specifically. This will also give you an idea of some of the issues/risks involved in rebreather diving.
Spend some time diving with willing CCR divers while you are on open circuit. Talk to them about their respective units, issues, service requirements, etc. There are several good units on the market. Some might be right for you, and some might not be a good choice for you. Take the time to find out about what makes a good choice before deciding on a particular unit.
Now, I am going to guess that it will take a good six months or more to do all of this. By then, I'll bet that you will either be 17 or very close to that. Once you reach that point, you will be less than a year away from being able to take the course as an adult rather than having to search for a way to complete your training before reaching 18. You'll also be able to chart new units coming on the market, upgrades to current units and the like. By then, you will have a very good picture of what unit is the right one for you.
Spend some time finding the right instructor. Beyond competence, you need one that is a good match for you. This will make all the difference in the world for your training, and for that important connection you will need for mentorship long after the formal class is over.
Rack up some more dives, and gain experience. Keep training, and keep learning. This will make your CCR training that much more beneficial. It will also make it easier. (Well, except for that buoyancy thing, but I will keep that a surprise for when you are in the water on your unit for the first times. :depressed
In the end, only you can decide what is right for you. However, you should not shortchange yourself by doing whatever you can just to find a way to get a unit, and to start training on it now. Go for the long term best benefit for your diving career. After all, you do plan to be doing this for a long time to come, don't you?
There is one last suggestion I am going to make. Before you make your final decision, buy and read this book:
Diving into Darkness. It is great reading, not at all boring. I now require this of my students that wish to take advanced level training in CCR diving. However, it is the kind of book that any diver, especially CCR divers and candidates, will find as a great read. (My web site has links to the books that I mention here.)
Good luck in the search.