Back in 1984 I met Paul Petzoldt, who was still going strong well into his 80's. One of my current mentors is 71 (has summitted Denali 4 times, the last time when he was 69). One of my skiing partners is in his 60's. Another backpacking buddy is in his 60's. My climbing partner is >50. Both of the Washburn's (Brad and Barbara) still hike, though not as much as they once did (I think they are in their late 80's now). I turn 40 this year, so, like you, I look around for peers in my age group and beyond, and happily I see them everywhere.

YMMV. Viewer discretion is advised.