Being unique is an incredible asset and something you should nurture. Being cool is quite frankly over rated and will fade with gathering maturity as conforming seems to loose it's luster. Everyone likes to be popular, but the friends you gather around you should be people who are like minded and not judgmental. Acquaintances fade and are numerous, but a true friend who can accept you as you are something rare. Wearing a Stormtrooper armour all the time is a bit out there - they are not the most comfortable things. Maybe compromising by wearing an item like the belt like Luke.
I thought playing a musical imstrument was always a great asset.
Being interested in Star Wars isn't nerdy. The last three films suck ( sorry ) and Lucas is not the known for his great script work, but the film is iconic for a reason and borrows on many classical stories. The design work is superlative and has inspired many great film makers of our generation - Jackson and Ridley Scott to name a few. It is one of the things that got me into art, as I wanted to be a matt painter after seeing the making doc on Star Wars. If you haven't already read 'The Fountain Head' I think that clarifies many things connected to being true to yourself and the dull grey masses of conformists.