"I lost my glasses, I don't know where I left them. Is it age?"
Age is used here like in other situations jealousy: an umbrella or catalogue of possible reasons we still did not pinpoint as the cause, side effect or symptom.
Forgetfulness, for whatever reason, including organic, stress, theft, Mobbing at work a too eager to tidy flat mate or nesting partner, the tooth fairy, etc.
Circulation problems and/or brain degradation from e. G. Hormonal or organic changes can definitely induce forgetfulness (sometimes reversible, sometimes not). Age itself not really.
Not everybody who ages get forgetful, quite far from that. Still a lot of people do, and instead of saying it inevitable, we can see what can be done about it (medication, community support, etc).
Not bitching, as usual pledging for more precision in the language in order to not normalise this or that idea.