OP, you have to ask yourself what do you look better with. Short hair or long hair and go with that.

Besides, unless you have more or less the same body type and look similar facially, you're still look a lot different from your T. I assume you must look very similar now, because you say you're twins.

Also I disagree with someone else who said physical appearance has little to do with real attraction. It does I'm afraid. It's not the be all and end all but appearance is what draws someone in in the first place to get to know you, and if you're very good looking it helps with that.