1. Congrats for getting into reading :)
2. I've been reading most of my life (nearing my 60s) and the one thing I do with every single book I read is take 'reading notes' on handmade index cards (handmade because I I like to recycle stuff, including old sheets of paper, and because 'm cheap. One could buy them new, obviously ;)) and while I read I take succinct notes of what I want to remind and of any idea or question that crosses my mind. I have a short pile of index cards and a pen or pencil and I jot stuff down as I read.

I don't write full sentences, save when I want to record a passage from the book, just keywords or, using my own shorthand, things that remotely looks like sentences. Using some shorthand makes it incredibly quick to write stuff down.

And when I finish the book I index the card(s) and archive them in a storage system that lets me retrieve any book or author I've read to check my notes, even years later. I often forget about the books I read... but I know my external brain remembers them for me ;)

I've not invented the system, it has been a thing since there was books to be reads and people willing to think and write. It also has been most formalized by Luhmann (he calls it a Zettelkasten, aka 'cards in box'), he was an academic... but one can start very simply without much, if any, consideration for academia either ;)

BTW, I do that for books and also for my own writings. It's all on index cards before it gets a chance to morph into a more structured project. Making it dead simple to retrieve any idea or comment or whatever I need.