>>2418364a few things that helped me with college:
going to the library as you said, also scheduling my work/study time. even if i didn't go out to do work, i'd treat it like an appointment, not plan anything during that time, etc.
the only way i could really get myself engaged with online classes is keeping my phone far, far away, and also going super hard on taking pretty/neat notes. i'd try and take notes before class and then make corrections to my notes during lectures (like if anything new was covered in class), or make flashcards of questions that were answered during lectures- for example, in my anatomy class i'd make a flashcard like "what are the layers of the skin from most superficial to least?"
physical notes/flashcards/books are really what worked best for me, as it gave me something to do and was a physical reminder that i'm doing school things and not just computer things. also, don't feel bad for occasionally being distracted during online classes! people get distracted all the time in classes, what matters is bringing yourself back after it happens.
best of luck nonna!