Help with a girl i really like?

ok so i have been good friends with a girl i know scince i was in about 3rd grade and within the last year or so ive become kind of attracted to her as shes gotten more and more mature but i also really love her personality and enjoy being around her. recently i went on a trip with her and some of her friends that i somtimes talked to. one of here friensds asked me when i was going to ask her out and i was kinda confused. she said that it was kinda obvious that i was attracted to her and asked me if i had ever noticed when she flirts with me. a couple of adults that we both know (and that i trust) had also told me that she acts differently around me a few months earlier. we both just turned 16 and i really want to ask her out but im extreamly worried that if i do she will be kinda freaked out and being friends would be extreamly akward. does anyone have some advice for me on what i should do?