AITA for refusing to share my inheritance with my siblings?

When my grandmother passed away, she left me some money in her will. My siblings were not included because she specifically chose to leave it to me.

After they found out, they said it wasn't fair because we are all family and I should split it equally.

I understand why they feel hurt, but I didn't make the decision. My grandmother made it clear that this was what she wanted.

I offered to help them in other ways, but I don't want to divide something that was intentionally left to me.

My family thinks I'm being selfish.

AITA?