How do I get my cousins to like me? Please Answer!?

Okay, so, well, i've always been the youngest on my mom's side of the family,when we get together for holidays, or just for fun. there are the uncles, aunts, cousins, blah blah. but of the kids, there is my 17 year old brother Michael, my 17 year old cousin Jackie, my 14 year old cousin Salina, and me. (im turning 12 in two weeks.) every time they come over, they always hang out with michael. they'll spend five minutes in my room, looking around, then leave for michael again. they hang out with him for like the whole time. they leave me alone in the house. sometimes i go into michaels room with them, but theyre talking about high school and friends and boy/girlfriends, and dirty jokes and playing world of war craft (WOW) and guitar hero 3. i know alot about that stuff (except high skool and WOW, and okay, ive never had a really serious relationship with a boy) but i go in anyway. usually i just sit there until i get bored, but sometimes ill have the "pleasure" of getting them food or a soda. (im a mini Jackie, everyone says, even her) .then i get bored and leave, but most of the time theyll tell me to "get the hell outta the room". how come they dont like me? and how can i get them to like me and spend more time with me? theyre coming over sunday, so please answer soon! thanks so much!