A socially awkward girl still has friends. I wish that more novels would show the friendships between people in more depth than “these people are friends because they talk sometimes” while glorifying the hell out of romantic relationships. (Sorry, pet peeve.) Those friends can have parties and get-togethers, and maybe they’re not at clubs or whatever, but they still get loud and have fun doing whatever they’re into. Knitting. Book critique. Magic the Gathering. Animal sacrifice.
Give her some friends or acquaintances that are not scarf-draped hipsters. Give her party people. Give her promiscuous girls and boys. Give her loudmouthed jerks she has to shush in the library but loves to death. People are not stereotypes. You can make two girls who both love trains associate with each other even if they have little else in common and it will still be realistic.
What if she doesn’t like Dostoevsky or Faulkner? Maybe her poison is Harry Potter or Sherlock Holmes or even Twilight. Maybe she secretly likes trashy books. I mean, Dostoevsky spends endlessly boring pages telling you exactly what his characters are thinking. Faulkner weaves a good story but you need to read through several hundred confusing pages before you can look back and realize the book was actually good. Not all “girls who read” read classics! And the classics are confusing and/or boring to some girls who do read!
For that matter, she doesn’t need to have interests and activities that are wholly niche. She doesn’t need to like the Foals or Tchaikovsky - One Republic and Beyonce are just fine. She doesn’t need to like obscure foreign films. Avengers and Indiana Jones are perfectly acceptable. She doesn’t need to like tea because it’s really watery and she thinks it’s just pretentious water. Maybe she really likes blue Gatorade. If your girl is into niche stuff, then being “niche” need not consume her entire personality.
Give her another reason for skipping on social events. Maybe, for example, she’s doing her homework or studying. (Surprisingly few characters in literature ever study and it’s a miracle how they’re still at the top of their class.) Maybe she doesn’t like the loud noises or lights, or maybe she just doesn’t want to stand awkwardly off to the side. Many explanations would be better than the “I’m better than them” rationale for not going.