old associations, synesthesia, or something in the middle ?

this feels weird to me because I knew synesthesia existed for a while but never actually considered I could have it..

the reason it hits me now is because I thought I just invented a revolutionary method to memorize dates for visual people : taking a paper and write the word (ex french revolution), but with the colors we see the last too digits (ex 1789 becomes light turquoise and deep blue for me)

isn't associating colors with things usual ? like, non randomly. friday was and always will be green to me, maths will alway be blue and german yellow, august yellow/orange and july a pale orange for some reason. and like, october is dark orange, I think it's common bc halloween etc so, isn't this normal??\

so I realized today : 9 can be deep blue to indigo and 6 light purple to pink. maybe bc they look alike? and 8 will go from light green to light turquoise and idk if that's because 4 is cyan or whatever. 0 is white (or very light grey), 5 DEFINITELY strongly orange idk why, 1 ugly bright yellow, 2 is light grey etc. though I think I associated 7 with deep green for a while bc it has always been my favorite number and green was my favorite color for a long time.

I'm puzzled by this bc I usually never CONSCIOUSLY see the associated colors, I have to think about what color would be the thing. like : I discovered TODAY that 3 is obviously red (I've never asked myself the question!), but if I see a 3, I won't necessarily see red if I don't think about it. idk if that would be considered synesthesia, or partial synesthesia or anything.