For myself, I prefer long hair. I tried the short-short cut when I was a kid and everyone mistook me for a boy (the cowboy boots and my brothers old wranglers didn't help the image). I don't think I would have that problem now with all my womanly attributes
but now I just like long hair better. Some women can pull off the short look, I am not among them. As everyone else has said, if you want to try something new, then just do it. If you don't like it, your hair will grow back eventually.
And by the way, what are you talking about "too old for long hair"? You look all of 17 in those pictures.