People tend to make others feel miserable because of their own "Miserableness". Usualy those who mock others for not having a girlfriend, end up with someone who they dont actualy love. Why? Because they feel the NEED to have a girlfriend, dispiting the feelings she/he has for that same person, just to say "
Hey look, i got a girlfriend! Im so pro. Aint i good?!".
You dont have to follow the same tedency. The "need" to urge to have a girlfriend. Things will come with time.
One thing you should do is to be yourself, but at the same time make the person you are with not feeling unconfortable. Tell some jokes, do some funny stuff (dont exagerate) and above all, just be yourself. We all have a funny side inside of us, but our "shyness" keeps it locked. Liberate yourself, be yourself and things will work out well. ^^
I used to be very shy when girls were around - but when i was with the guys, i was always telling stuff and making them laugh and doing silly things. xD then i met a very "wicked" (in a good way) girl who just opened my eyes. (she is my girl-friend. Not in a romantic way, its like my best-girl-friend, the best female friend) and she told me that girls were as shy as i was. I was like "REALY?!" - So you pretty much see how primitive i was - .
Yeah, girls can be shy aswell. Probably even more insecure (or not) then boys. Because we (boys) usualy are pushy, and girls dont like to be pushed. (Well some like, but i think the majority does not) well depends on the way your pushing it anyway. (Not realy an expert, lol)
Oh, and dont quit if you get a "no" as an answer. Usualy girls dont realy mean what they say. Its just that first impression, or that actitude who she dislikes on you - but it doesnt mean she dislikes you at all.
To end, im telling you from my own experience. Not like im an expert even so, just some tips who might help you. There are girls with different actitudes/feelings, thats what makes each of them UNIQUE. So the time will come, and till then, just be yourself. Kick the "shyness" in the ass and let the "true-you" within you merge.
Hope it helps somehow - not an expert but might be a little light, who knows.