Should I be upset about this?

My older snobbish cousin is having a graduation party for graduating high school. Everyone is my family is so happy for him and stuff but me and my twin sister just graduated eighth grade and nobody knows. The party is being held by my aunt at my rich great uncles beach house (not her house) Its a really big deal and lots of people are going. My mom said shes not going to bother throwing me and my sister a party when we graduate high school because she doesn't want to deal with all the drama. I feel like I'm not as important as him or something. My mom said I'm being weird about it when I say "I graduated to" or ask "will I get a party". I'm not trying to sound spoiled but its like no one cares. I know eighth grade graduation is not as important as high school graduation but don't I deserve t least a phone call. And would you feel bad when you graduate high school and don't get party but your older cousin whose just as important as you did? Please use your honest opinion.