How do you not be insecure?

I talk really loud and stuff like that and i know sometimes its annoying or people think i am really weird. BUt i do not want to change because of others opinions. I have lived in the same area since i was 5 and all of the people in that area have gone to the same public school since they were little. I have gone 2 a private school. Next school year i am going 2 the school. I already have two best friends who go to the school and i know a couple other people. They like me despite my loudness. I know other people will like me to but every once and awhile i fell scared that i will be just another annoying girl no one likes. I know it is stupid because i already have friends but any suggestions on how to feel less insecure??