<human>: Can you condense the text into three sentences or less?

I am currently studying at a university, and I quite like it. But there is one thing that bugs me, and I need some tips on how to get out of this.

There is 53 people in my class, and > 1000 studying at said university. I am 20 years of age, not very tall (slightly above 5"10) and not very muscular. My classmates are 23 and above, and I keep being treated like a younger brother when we're not studying. This makes me feel like I'm not taken seriously, beyond the intellectual/technical level (been fooling around with graphic designing/sound engineering/producing for quite a while, got some grades in said things and think of myself as pretty decent). I helped my friends with graphic designs for quite some time, but recently gave up since it didn't give me any respect, but the role "the technical youngster that of course will help me out" instead.

Since I have no real life-experience (went straight from upper secondary to university with only a summer holiday between) I don't seem intresting at all. People speak of the times they were Au Pairs in the US, went travelling across the world or had a long-term job. I sit there, thinking "What the hell can I mention about me?".

This also disables me quite a bit when it comes to girls. If I'm not DJing somewhere I go out for drinks with other people from school on the weekends. When I try to chat some girl up, I just get friend/niceguy/younger brother-zoned. The older people at the club gets selected first, and what's left is the abstinent chicks, the girls in relationships and the passed out and (often) butt-ugly girls.
<bot>: not taken seriously at school due to my age, disables me in many ways. How to be seen as "equal"?