i’m 35 and only got into music a couple years ago— not from a sheet music, but from play
i think the same neurological pathways you use to sequence musical tonality is the same as stringing any sequence of thought together.
my hypothesis as to why reading hasn’t helped train thought— the way people write isn’t how they think. it appears words go from their brain to the page, but there’s so much thought that goes into making the flow of their content more like music than their raw brain feed.
good luck!