How to live as a shut-in?

Im the definition of a shut-in. I never leave my house unless its to get a haircut or something EXTREMELY important. I got my GED so im not going to school anymore, and in two months ill be turning 18. I have no friends or family but im perfectly fine and happy by myself. What affects me deeply, is when people around me judge me because im anti social. I hate leaving my house because even little kids in my neighborhood ask me why im always indoors. I dont understand why people feel the need to judge me and put me down all the time when i never judge them. Its hard waking up every day and the thought of going out chokes me up (literally), because im sick of people just staring at me and looking at me as if i was an alien. Every one else just seems to fit in their roles on this earth and it hurts me to think that i will never have my role. Everyone just says "its all up to you, you have to change or stay the same forever", and although ultimately its true, i feel like its really unfair because i never chose to be criticized or to get put down to the point where my brain became afraid of socializing with other humans, so why should it be my choice to get better. Im also sick of being labeled as someone with "mental problems" or "he has issues" or "no life" just to name a few, it makes me feel less than everyone. Its so hard to have any motivation or goals when you feel this way but i dont know what to do. Any advice would be appreciated. Thx for your time.