Which one should I pick!? Help please :(?

I have very curly dark brown hair that is a bit longer than my armpit length, and reaches the bottom of my boob when strait. I am tired of having boring one tone hair, so I want to change it up. I've had golden highlights before and they were awful. I want to add either blue or red in my hair, but I don't know what color to pick. Also I don't know how to put it. A streak? The tips? The bottom and back? Highlights? I need help, what color and style would look best for my hair? Also I am 15 years old and a girl. Thank You <3