AITAH for telling my dad's parents that I don't want them at my graduation when they said I wasn't their real grandson?

In November, my (18M) dad's parents and my mom got into an argument because they mentioned they said they decided to start a college fund for my brother (11M). It wasn’t even brought up, they just decided to share it on their own. My mom was confused since they mentioned it out of the blue but thanked them. She asked them why they decided to make one now and why they brought it up.

They said something about wanting to do it for their grandson and making sure he's set so he doesn't have to worry about paying for college. My mom then asked if they had started one for me, and they said I wasn’t their “real” grandson, so the answer was no and they didn’t have one for me. They added something about how I’d “get something else” and accused my mom of expecting too much.

For context, my dad adopted me when I was 5. He started dating my mom when I was 2. I don’t know my biological father personally, but I know of him. He died when I was 3, and my mom told me he wasn’t a good person and was in and out of jail. My dad is the only dad I’ve ever known, and I always thought his parents accepted me. But hearing them basically say I wasn’t their “real” grandson hurt. It wasn’t even about the money. It was the fact that I was excluded and realizing the only reason why was because I wasn’t my dad's biological son.

The argument happened right in front of me and my brother. Just a few days before Thanksgiving. Since then, I’ve viewed my dad’s parents differently and tried to keep my distance from them. They eventually apologized for saying I wasn’t their real grandson, but only because my dad basically forced them to. Over time I realized I didn’t really care anymore, but I just loved them more than they loved me.

School is almost back in, and I take senior pictures soon. My dad’s parents were over for Christmas, and my parents brought up me taking pictures. That led to my dad’s parents talking about how excited they were to see me graduate and how they couldn't wait.

This confused me. It honestly did because a month ago they basically told me that I wasn’t their real grandson and now they're excited to see their "grandson" graduate.

I told them that they weren’t coming and that I didn’t want them there. Of course, this shocked my parents and my dad’s parents. They asked why, and I told them I remember them saying I wasn’t their real grandson, so it doesn’t make sense for them to want to come to my graduation when they have no ties to me.

My dad looked upset, and his parents were too. His parents basically said I should move on since they already apologized and meant no harm. I told them that when they apologized, it was only because my dad told them to. After that, it got awkward. This happened during Christmas, and I haven’t seen them since. My dad told me they’re hurt by what I said and that I should apologize and let them know I didn’t mean it and that I’d still like them to come. I told him I meant what I said and that I don’t want them there. It’s not like I can stop them from coming anyway, but I’d prefer if they didn’t since they have no reason to be there. He says their feelings are hurt.

It’s honestly embarrassing to think they’ve been my grandparents my whole life, only to find out they didn’t even think of me as their grandson. My mom says she agrees with me but thinks I should consider my dad’s feelings since this puts him in a hard position and wants everyone to be "family." I’m not trying to hurt my dad, but I just don’t want his parents at my graduation when I just found out they didn't accept me.