Not invited to aunts wedding?

I am the first niece to my aunt and was not invited to her wedding. I had my grampa fly out with family to attend the wedding and no one ever asked to see me. We all live in the same city and my mom went with her boyfriend and my half sister. It’s been about 1 1/2 since this happened and I refuse to talk to her or grandpa because I won’t be that “bastard child”. I refuse. Even more disappointed in my mother for taking her bf and not me.

Note: I didn’t have a bad relationship with my aunt. She just choose to always fight and accuse me mom of things she didn’t do and I played no part in it.

Am I wrong for feeling neglected? I hadn’t seen my grandpa in years and the fact that he came and I wasn’t included in a family wedding hurt.