Sendaz doesn't quite give enough information. The part I'm about to give may be off by a couple of years, but it's as accurate as my memory is.

The first known otaku were at the Denver Data Haven; the boxed set's in-game year was 2055, and they'd had otaku there for a while; because of the way they describe it, while the 'tribes' must have been there for at least a decade, actual otaku may have only popped up a year or so prior - been a while since I read it, so I can't say for certain. In any case, the two otaku tribes generally pulled their new members off the street anywhere between age three and eight. After a lot of time on turtles, those who would become
actual otaku would finally go under the knife to get a datajack when they're (I
think) ten or twelve years old. With all the practice over the past number of years, they become red-hot deckers in short order, and -- this is estimated, but I think it's a good estimate, considering the Michael Bishop story - in a year or so are brought to the Deep Resonance.
So. Call the oldest likely otaku at date-of-publication 16; that puts birth year at (2055 - 16 = ) 2039. If you're playing in 2079, that's 40 years old, so 44 is along the outside of possibility - though Sendaz is correct, even with Submersion most otaku had lost their abilities by age 30.