My cousin KNEW it was my bday but did not call or anything to wish me happy birthday......?

You have to remember that if you live far away and don't see each other often she is probably busy with friends who live close by. If you can't be there through life's ups and downs with her then long distance kindnesses and birthday presents really don't add up to much unless you're really close and writing letters to each other all the time. She simply isn't showing that she is interested in a really close relationship with you. Not many cousins have that. You have to factor in the adults too. Sometimes if the adults in the family aren't getting along well for whatever reason, then there is pressure not to be too close for instance if her mom and your dad are in laws and don't like each other. You're better off finding new friends who live close by and then let it go. She may be going through a phase in life where she is extremely busy or there could be a thousand other reasons. You should give her a call and let her know that you'd like to be more involved in her life and see what she says. Sometimes, asking the person is the best way to find out.