Long hair looks good on probably all girls. If you are interested in growing it long then do it for yourself. It's your body and your interest. Just remember to take good care of it. The longer the hair the more care it needs.
I prefer to keep my own hair short because it's so thick that I can't deal with it when it's long. However, when it's short, I need to get it cut once a month to keep it looking good, so it's very impractical for being a full-time student in a very unfashionable city. I have to wait until I go home (across the country) to get my hair cut so I have been growing it out a little.
However, in your case, the best way to ensure that your hair grows long and well is to get the damaged parts cut regularly. If your hair is too damaged, it won't grow. So even if you just get the ends trimmed or dusted every few months, you'll be better off. That length sounds excessive to me. Unless you have really manageable hair, it's always going to be a mess.