Backup friend?

I kinda just feel like a backup friend, my closest friend from 2nd grade imma call her raspberry has been replacing me for months with this girl her age we’re gonna call orange, they are sophomores and I’m a junior in high school. They hangout and if orange can’t hangout raspberry goes to me asking to hangout, every hangout it’s cause orange can’t go. But I’m always there for her, for her concerts and if she needs someone, I’m more mature yk. She doesn’t like going to orange for stuff cause she doesn’t take things seriously. But idk I’m just feeling like she’s using me mentally? Idk. Alots going on rn and she wants to hangout to go to this haunted house this weekend and idk if I really wanna go be a backup. She’s turning preppy and acting like orange and even is looking like her, got a nose piercing like her, dyed her hair and cut it just like hers and dresses sort of like her and does makeup exactly like hers. Orange is city preppy kid, raspberry is a country idek how to explain it, they wernt alike. Maybe in paranoid or going crazy or overreacting.

Thanks for listening hope it wasn’t confusing.