I don't think 16 is too young for starting rebreather diving. That is about how old I was when I started. But as previous posters stated, you MUST have the right instructor. My instructor was a former Navy SEAL instructor and a certified SCUBA sport instructor.
Some of the things you do almost subconsciously with OC is unexpectedly different in RB diving.
Glad you mentioned that. It's those subtle differences that make RB instruction/training for younger folks that much more risky. Additionally, scuba training standards try to make this niche accessible by balancing risk and market share. I personally don't agree with the starting ages of suggested by most instructional agencies. Especially, in this niche of diving. I remember years ago when they tried some "scuba wonders" program for little kids, only to rescind the program after some kid croaked. It eerily paralleled some aspects of the world's youngest flyer who recently died.
Having trained kids in introductory RB classes, and worked with them for decades I am more than happy to let them get certified at a later age. As a FYI - teaching younger divers places a higher liability upon the instructor. Namely, a higher standard of care. This effectively means that should a kid get injured while diving you (as an instructor) are liable (for life) in many jurisdictions. Who needs that? Additionally, teens are developmentally different mentally and physically than say a 25 yr. old. Personally, I don't trust young adults to make the best decisions.
While we might enthusiastically encourage someone to learn as early as possible, (just because we love RB's or because we think we can) I am more than happy to say get certified later because having seen the sport emerge many years ago, and witnessed the ensuing fatalities that followed (with adults) I am happy to encourage them when they have a range of hard-diving skills (psychomotor) under their belt and some range of muscular development...especially for the waters of NJ where the conditions are sometimes anything but benign.
So, I don't care what RB (MCCR/ECCR/SCR) any young-un' can afford...it's get experience UW first, find someone who cares enough to see a young techie through to adulthood and instill a attitude/hard skills which would make them a wary RB diver. All too easy to get hurt on these things.
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