If you've never fought before, are tall, and slightly lanky, then no doubt you're going to get your ass whooped. Big time. Make no mistake about it. All the guy would have to do is slap you in the face to knock your glasses off. And then maybe tell you to go back to your orgy with Harry Potter and Warcraft. What woman wants to sleep with a tall, nerdy dork?
You see what I just did? I bet you want to jump in to this screen and punch me in the face.
Now ask yourself, why? Why did you just let me bother you, even when I don't know you? Why are you taking yourself so seriously?
The problem isn't those guys or those girls.
The problem is you. You're doing something, saying something, acting something, looking like something that would allow other guys to make fun of you.
You want to fix it? Start with self-improvement.
Hook up with a personal trainer so you can train your body properly. Change your diet to add on some weight. Read up on some GQ forum about styles and looks to change your clothing. Go out and develop interests outside the "nerdy" zone. Don't get me wrong, I love playing video games as much as the next guy. But I don't go to the extreme that some nerds do.
Most guys don't make fun or put down other guys out of the blue. They would have to see you as somebody who looks weak, acts weak, talks weak, and ergo is weak. Are you any of the above? If so, fix yourself first.
Then worry about picking fights.