u/BM_Boutique

For context my parents are divorced and my mother has custody of all of my biological siblings which are my brother and my two sisters. My dad has a girlfriend and she has a boy and a girl. Its not that I don't like them but I have only known them for less than a year and since my dad and his girlfriend aren't married, they technically aren't my stepfamily yet.
Now here lies the issue, my school has a set number of tickets they give out for family members to come an attend graduation, this year only 8 tickets were given. If you counted up everyone I had mentioned previously then you would notice that it totaled exactly to 8 people which should be perfect right?
However, way before I had even met these people I invited my cousin and his two younger sisters who I've been close with since we were like 6 years old. I wasn’t able to go to his graduation because he ended school before me however I am still close with to this day and I would really like him to be there at the ceremony.
I told my dad about how I invited my cousins long before his girlfriend was in the picture and he brushed it off and said that they had to find some way in. I dont know how to tell him that those three tickets will be going to my cousins instead of my stepfamily. It’s not like I would be excluding them from my other graduation plans but it would only be the ceremony that they would miss. Ultimately I feel like its my graduation and I should have final say over who I want to have there.