Thank you all.
It's odd. Until now every age I've had had a distinct "feeling" to it. It's difficult to explain. For example, 10 felt free and energetic. Perfect, really. 12 was... forboding. 13 felt strange and awkward, which is actually pretty normal. Like a 12 with an upgrade.
14 felt, oddly, like 10 with more maturity. Much less awkward, more free and breathable. 15 felt... heavy. Like I was being weighed down...
16 felt pretty nice, really. It felt like 14 with more restraint and maturity, starting to learn more about myself and starting to come to terms with the fact that I've grown up. 17... doesn't feel like anything yet. Despite my joke above, I guess my body hasn't reshifted yet. Or, weird scifi jokes aside, my mind hasn't let it sink in.
I suspect, when it does, it will carry the forboding feeling of 12... because I know what I'm one year away from...