What should i do about this mean girl?

The girl sounds like what is known as a social climber. This means someone who will make herself look better by trying to make others look bad. She's bullying you for some unknown reason, and about all you can do is not let her get under your skin. If she tries to embar you in front of people, then you have one of two options. The high road: you do what you do now and ignore her the best you can. The low road: you call her out. point out that she's being immature or annoying (you know it's true.) Either way, bear in mind that she and girls like her are a dime a dozen and you won't have to deal with her forever. Someday, you'll be living the dream and she'll be stuck in a dead end job and a dead end marriage.