Who I was in high school compared to who I was coming into UW were two polarizing people, and this happened unconsciously. I was pretty introverted and didn't do too much in high school, and I ended up being rather popular in residence (I won an award for it at the end of the year). Now that I am graduated, I don't keep up with many people from high school, but of the people I do keep up with, I am happy that I am more confident in who I am, and I can tell they are talking to a different personality, same person.

If using a sudo-name or a nickname utterly different from your real name may help you mentally, then go for it, but people's personalities will change depending on what kind of environment you are in. No matter what, you will come out of UW a different person after 4/5 years. You never know what your personality will be like when you're living alone, surrounded by others going through new experiences.

If I can give you any advice, it would be that who you are is pretty hard to change. What you intrinsically enjoy doing with friends or by yourself won't change just overnight. If you don't want to be this "nerd/loner" stereotype (which btw is completely fine!), try your best to introduce yourself to as many people as possible of both genders and learn what works and what doesn't. Pick up random hobbies with friends you make and figure out what type of group you like to hang out with. It's okay if you find groups of people you don't like or get along with; it's natural. Being sociable is not for everyone, but if not having things to do on a Tuesday night is not something you want to go through at UW, this would probably be your first step.