I think that's too old? Metahumans are, barring the ones we've made, known to be born as ones and the Leviathan only crashed down in 2001.
If he was, at minimum, 86 in 2066(1 year before the Movement), then he would have been 21 when the Leviathan crashed. And also been the first to have become, rather then be born, a metahuman.
On a different topic, I'm expecting Yara's side effect to be that she's super powerful while asleep, but massively weaker while awake. Which also provides a handy excuse to hide Project Prometheus: turns out she's been a metahuman for years, she just never realized her dreams were more then her having lucid dreams, and since she's so much weaker when awake it was never noticed.