It's very possible if you want it. Ask yourself how you want people to see you. Find the answer. Then dress the part. Whether that's getting in shape to feel good about yourself and be more healthy, or a new haircut, new clothes. Getting out and dealing with people on a daily basis as well gives you the exposure to adjust, stop caring what people think, and just be comfortable in your skin is one key to gaining self confidence. Which includes doing things that put you out of your comfort zone; bonus points if it embarrasses you. Because the more that happens, the less it bothers you, and the more confident you get. It doesn't become a big deal anymore, you aren't afraid of messing up, looking stupid, or feeling anxious about introducing yourself if you've practiced so many times. Eventually you just get comfortable and can genuinely focus on the other person instead of yourself and your insecurities. Confidence is being sure of oneself and your abilities. Fake it until you make it.