If I may ask: how old are you?

I used to have the same ability (and am still well above average) but it's lessened over the past 3 years or so. I've been trying to work out whether it's due to a) age (greater number of life experiences and/or memory naturally less good), b) studies (prioritising studied material over episodic memory), c) greater socialisation (I used to be fairly isolated, so it's possible that there were just fewer noteworthy things to remember), d) some other factor.

And relatedly: do you also have that sense of frustration when people keep repeating themselves over multiple conversations? It took me a long time to realise that they weren't doing it on purpose and that not everyone can remember what they've said to who in the past.