How should I respond to people like this?

So to any of you who want to try and answer this I'll try and keep this as short as possible, sorry if it's long. But i'm a 15 year old male - I play guitar and sing; I'm usually quiet at school, home, work. The only time i'm not is if i'm singing or with my really close friends. But when I go to school, i know like 80 percent of the school but so it's not like i'm a loner or anything but people will make dumb remarks about me. I'm the type of person that sings and plays guitar so i'm calm and quiet most of the time. Like for example: i walked into cl and i have shoes that are skinny around my feet - "Pumas". This girl says i have the same shoes you're wearing girl shoes and the cl all looked at me - this was when i was walking in. They are black shoes and white on the side with a stripe and i got them in the mens section in men sizes so i know for a fact they're mens shoes. I said no i'm pretty sure i go them in the mens section maybe your just wearing mens shoes. How should i respond to people like this? When they make dumb comments, i want to be remembered as a nice person. Or if someone says like **** you or something rude.