I enjoyed reading Sheldon Axler's book Linear Algebra Done Right, a couple of years ago. I read it on my own, and did all the exercises (except for one which needed symbolic computation software, which I don't have), so it must have been fun!
Many, many years before that, I read most of Roger Godement's Algebra (which is mostly linear algebra), and Hartley and Hawkes' Rings, Modules and Linear Algebra, but I didn't bother doing many of the exercises (correction: I do seem to have done nearly all of the exercises in H & H, but I can't remember a thing about it!), and I can't say I actually enjoyed reading either book, nor am I much good at retaining anything I've read (for more than a week or so at most).
I have only recently, very late in life, slowly started to enjoy doing mathematics more, but for the last couple of years I've been hitting a brick wall in my mind again, and haven't been able to study much at all.
I used to treat my own mind like an unconscious machine which I could exploit to get good results in examinations, but I never, until recently, seem to have treated my own mind as a human being - if that makes sense to anybody!
(I fear it may not! Not all my problems are Aspie problems, and I feel I must be a bit mad, even by the Aspie standard of sanity, which probably makes far more sense to me than the NT standard of sanity. So, just ignore me if I seem to be spouting nonsense.)
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Age: 60. Sex: male. Gender: OK I give up, please tell me
AQ: 37/50; Aspie Quiz: 110/200 for Aspie, 82/200 for NT
Almost certainly not Aspie, but certainly something like it