I first noticed something different about 7/8 years ago when I was at my brothers house, and he had a book on memorization techniques. I picked it up and by chance read about visualizing things as an aide to help. I asked him and his wife if they could do this black magic and they could, since she was a Doctor she offered a couple of explanations - brain trauma, tumor, or the less malign you are just not a “visual person”.
At this point in my life I was living in a shared house, I reached out to my room mates they thought I was making it up or as above suggested tumor.
It was hard to google what I was experience as it was so nebulous, there were no keywords to help identify key information.
So I let it be and as far as I was concerned I had always been like this and all that is changed is I learnt other people were not, and when they said “picture it in your head” - they actually meant it.
Out comes BBC with the University of Exeter research, 2/3 years I got two apologies from my old housemates and a term to google.
My mom was visiting when the research came out, so just for kicks I read the questionnaire from the BBC put out, turns out like me she also had aphantasia.
Edit wider read history:
It's weird, I don't have much memory of my childhood. Ask me facts about it I can tell you. I did and still do try play music, my first instrument was Trumpet - I could never site read a stave and notes on it, I would always had to cheat and write finger positions underneath. I still play bass and guitar but I am not musical, its mostly about patterns with the hand. I can't hear music in my head. My timing on 4/4 and simple signatures is alright, 3/4 i'm terrible.
I always enjoyed graphic design, but I was never a master creative and I wish I knew this when I was in school I would have changed my options.
The most depressing but of aphantasia for me is the fact I can't recall those I love in my head, and it seems people can this is the only way it's really effected me emotionally, I find now I place a special emphasis on photographs .
In university I did research into Synthesia for a computer application, mainly as I thought it was so out there reflecting back I can see why it perked my interest, it's the complete opposite of what I thought was normal.
Currently I work a software engineer, I have a terrible memory for things told to me in passing. But I am very tenacious with facts and recalling information I researched on topics I'm working on.