Clothing is not the most important thing for Jews; our insides matter more than our outsides! As long as we dress modestly we are in accordance with halachah (there are indeed some specifics of what “modestly” means and any orthodox rabbi can explain). Most contemporary “Jewish” clothing styles started out as gentile clothing styles so it isn’t like they are Torah from Sinai.
I do suggest NCSY if you are in a public school. Helping Jews in public schools is their main focus and they have guided many young Jews to the right place. You may end up more charedi or more modern, but they can help you regardless of the direction you feel is right for you. And as you figure out where you want to end up you will naturally dress accordingly. NCSY has a nice internet site ncsy dot org.
Good luck!