How can i get over being shy to girls i am 19 and dated once and i

I just dont understand why im so shy

I had the same exact problem, the best advice I can give is just relax, just be yourself and don't be afraid to get out of your comfort zone and talk to girls, just talk don't try to be cool don't try to impress them.
Ask them questions about themselves, who they are, what are they interests, what do they like to do, if they are in college, do they have a job, do they like their job,

Over time you will begin to relax and will have no problem talking to girls, just be nice and sweet don't be a jerk or a a**hole that won't get you anywhere (I speak from personal experience).

I was shy up until my fiancee and I got together when I was 16 and all the worrys that come from being shy went away.

When the anxiety kicks in from being shy just stop and ask yourself whats the worse that will happen? I guess a girl could reject you, but hey your 19, this isn't high school its not going to spread like Michael Jackson dying.