I cant talk to girls?

im 15 and i cant talk to girls at all,i cant so much as look at them,so when i talk to them i have an earphone in and listen to music to try and stay calm.when i do talk to a girl it gets awkward real quick and i want to leave but that would be rude.i can talk to them when im txting and stuff but when its in person or over the phone i dont know what to say.i get shy because when one of my friends tried to get me in on a conversation they looked at me and i made my answer short and then i pretended like i was looking at something.....am i just not good at it??