I'm afraid to approach females

I'm afraid to approach females. I'm 17 and it's hard for me to try to talk to new females. Once I've known a female for a while I can talk to them no problem but by then I'm in the friend zone and there isn't much hope for me. I have and 8" penis and I've used that to help me hook up (have sex) with a few girls and now I'm trying to always hook up but I can't do that if I can't be brave enough to approach new females. SOMEONE PLEASE GIVE ME SOME ADVICE.