Most Helpful Guy
No. It could be your attitude, if your not giving a positive vibe or making people comfortable and making them feel like your approachable they won't hit on you. That's a big problem with shy women, shyness can be misinterpreted as disinterest really easily. Some people just have a "resting bitch face" which also makes them seem unapproachable. Body language is a big factor as well. Could be any number of things.
Most Helpful Girl
Maybe it's the way you present yourself. Your posture, body language, and expression. I don't think you're ugly! Just seem open or make the first move! Good luck! You're still so young, you've got a lot of time, don't worry!