Confusing Predicament

So I (M) have a friend (F) that I go to school with and we basically have every class together. We have similar interests as well as have good (my perspective) chemistry. We have known each other before but only recently started talking more and sitting next to each other in class. I am a bit of a loner in class if I am honest, not anti-social I just prefer to sit in the back of the class because it just feels nice that no one is behind me, etc. Ever since class has started we’ve been sitting next to each other, as per usual I sit in the back and she would come to sit next to me in all of our classes. She doesn’t have many (good) friends in the class so it makes sense. My plead for advice comes for outside of class. Outside of class we hang out, we have lunch together as well as study/do homework together. Is there something going on? I am quite oblivious to these sorts of things. I happen to socialize well with most people but when it comes to romantic aspects I usually fall apart and am way too oblivious (from past experiences). I’ve asked my younger sister and she said “she likes you” but idk how valid this perspective is.

My friend is closer to anti-social than I am to it. She is shy and doesn’t really talk to other people in the class (one of the perks of sitting in the back is being able to see who sits where and with who). She also sometimes doesn’t give me any indication if she wants to hang out outside of class, so we kinda follow each other around, I don’t mind her following me around as it’s nice to have someone to talk to, but I am not sure if she is annoyed I sometimes (not often) follow her around. I also would like some advice on this situation as I think she would be shy enough to go with the situation unless I was unbearably annoying.