To go or not to go to the graduation??

Ok, I am 22 years old. I am almost done with my bachelor's degree and I own my own house. But my mom and 8 year old sister live with me. My cousin is graduating soon and she told my mom about the graduation over a month ago but not me. She actually still has yet to tell me about it. When she gave my mom the tickets, she labeled them "Debbie and family." (Debbie is my mom's name). I feel like she has not even invited me and does not have the courtesy to consider that I am not a child and deserve a proper invitation. Help!!!