I don't think there's a conclusive answer to whether long hair or short hair is better. I remember a girl in my class who had really long her, and told everyone she was going to cut it.
Even the teachers were trying to convince her not to do it.
But when she showed up the next day with her new haircut, the entire class really liked it!
When picking a hairstyle, whether long or short or whatever... The most important question is to consider whether a specific style suits your face shape.
Any good hairstylist will tell you that your hair is like a border for your face.
If you have an iPhone, then I'd recommend trying out an app like Hairstyle Magic Mirror (https://itunes.apple.com/gb/app/hairstyle-magic-mirror-change/id429947895?mt=8)
It basically allows you to alter an image of yourself, to see what different hairstyles would look like on you.
Maybe I'll download it to see if I'd look hot with a bright blue mohican...