How do I make myself feel less insecure?

[thecablegur3949]

Next weekend, some of the girls from my grade are going out for my friend's birthday. Two of her closest friends started a group on Facebook for her birthday event. The birthday girl invited me a few days later and I didn't know about the whole thing until she invited me and afterwords added me to the Facebook group. While looking at who else was invited, I noted that all of the other girls were added the day the group was made. I was not offended because I am not close friends with the girls who started the event. They had only invited 10 other girls, excluding themselves, the birthday girl, and me.
I am in tenth grade now, so as you can guess this made me doubt myself. I love the girl, and I am pretty good friends with most of the invited guests. I know that the group that was invited will be 'the group' in high school for the next two years to come, so I want to take advantage of this opportunity and really show them how great I am. Sometimes, they get together at someone's house and I am usually not invited. I am not talking about those super popular girls, because given the fact that my grade is small, the popular group is pretty big and there is a good chance of me getting in.
When I feel comfortable, I know I can be myself around them, which is usually the funny side of me that can laugh about anything and just have a good time. On the other hand, on a day like that day, I will feel self conscience and I know that when that happens I tend to act awkwardly.
Do any of you have any suggestions as to how I can make myself feel prouder and more confident before I go? I really want to impress them but at the same time I don't want to worry about myself every second.
These girls can sometimes act very tough-like and I know how to defend myself. Really, I want to prove myself to these girls and show them that I am the type of person that they should add to their group.
I know that some of you will respond with 'you don't need to prove yourself to them' and such, but I am past that. I started developing depression because I tried to convince myself of that, yet subconsciously I couldn't believe it. I do have some friends, yet none of them are very close to me. The birthday girl is like a childhood friend, so we sometimes hang out. I am not super close with any of the girls in the group, but we have our moments.
I was strongly considering becoming extremely close friends with one of the girls, and slowly build on and add on other people. My only problem is, I can't just add a friend. My personality is that I need to know someone for a long time before I can go to them about anything and joke around with them instantaneously. There is one person in that group who is like that to me, but she really likes to have a lot of close friends so I can't really build on her. Do any of you have suggestions as to how I can connect with the others? Most of them already have really close friends in the group but I am not really good at making close connections with people in a matter of days. I really am open to suggestions.
If you have personal stories that really helped you out, I would love to hear them. These girls are not all about money, because some of them are really not that rich, but they do enjoy talking about exciting experiences in their lives.
I am not on bad terms with any of the girls, which is good, but I want them to know me a little better so that they will accept me and I can a) put my sub conscience mind at ease that I did what I could and if they don't accept me then there is nothing more I could have done b) become better friends with the girls and get invited to more events.
You may think that I am super materialistic and only interested in popularity, but I can guarantee you that its not the case. If you think I am like that, I do accept personal criticism as long as it means something and you really think I could improve in that area.
Thank you all so much for your time, because I am sure that most of you have gone through high school so maybe you could give me pointers if you were popular or if you could go back and change something?

[Dottie R]

What does this have to do with Cooking & Recipes?

Just be yourself or you'll never know if you have real friends or just people tolerating you.

[hannahbrooks]

Wear amazing clothes! Act loke you dont care about school gossip and like try to become bffs with rhe girls! It could be really fun to be in the popualr group