My grandfather paid off my twin brothers [23M] loans, but not mine. [23F]

Title says it all, but to add context: I was studying abroad when my mom called me with great news, that my grandpa was paying off my brothers student loans. "He'll probably pay off yours too, you know!" I didn't want to assume but he has helped me and my brother a couple times over the years and when he did he always gave us both an equal amount, so I started to believe it to be true. I didn't say anything specific to him about it, but I tried to bring it up a couple times casually and he never said anything so I assumed maybe he forgot or something,
It's been a few months since then and I'm currently working and have to start paying my loans in a couple months. My mom reminds me I should call my grandpa about those loans, but I felt really uncomfortable asking him for that much money. So I asked my brother if he would bring it up with him and just see what he says. Well grandpa says no he wasn't going to pay them off.
My brother and I are twins, we went to the same college, we walked at graduation the same time. My loans are a little higher than his cause I studied abroad but I figured he would at least give me the same amount he gave my brother. The only difference is that my brother majored in interdisciplinary studies and I studied journalism and Spanish. Oh, and he's a boy and I'm a girl. It's one thing if my brother graduated years before me but our grandpa knows that we both graduated and as twins we obviously went to school at the same time. I would have never assumed that anyone would help me with these loans, and I feel like a **** even complaining about this but he paid off my brothers but not mine? It feels so unfair. Today is our birthday and I just got off work and I have just been crying since then. It feels really personal.
I guess I'm just asking for advice on how to handle this situation. Obviously there is nothing I can do here, but I feel a lot of hurt towards my grandfather and my twin brother right now. If anyone could help me be ok with this I would appreciate it. He gave my brother 30k and says he won't give me anything. Why didn't he give us 15k each then? My brother didn't even have to ask for it, my grandpa just called him up one day and asked him how much he owed and said he would send a check. Why do you think he did this? I feel like he must hate me.
TL;DR: Grandpa paid off my student loans for my twin brother a few months ago. Everyone assumed he would help me too but he just said he wouldn't. What can I do to not hate him and my brother, and maybe to not take it personally even though it feels so personal?


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