I feel like I’m behind by not having my period but I also feel ahead because I’m more developed then my other friends without their period

It's totally normal to feel like you're in a weird in-between spot with puberty, because everyone's body really does its own thing on its own timeline. There's no such thing as "behind" or "ahead" when it comes to getting your period or developing breasts, because every body is just different and that's actually super cool.