Death of Birth-grandmother

I guess I am a child of stepparent adoption. My mother remarried when I was two and I was immediately adopted by her husband and have always considered him my father. I also never knew my birth father and only know his name because I accidentally overheard a conversation between some family members. However, as a child, I did have contact with my birth father's parents. Specifically, his single mother, and his father and stepmother. They were like extra grandparents that I got to see at Christmas. There was also an Aunt that I vaguely remember. Over the years we lost contact. I don't think there has been any contact for at least 13 years. Still, I think about them often, and I wonder if they ever think of me. In a recent search I discovered that one of my grandparents passed away about 6 months ago and I felt so heartbroken that I let them fall out of my life. I wish I had tried harder to stay in touch, but I was just a kid, and they lived far away. I'm considering visiting the cemetery to try and find some sense of closure, but I don't know if it would really help. It's strange feeling so much loss over a person I really barely knew, but I feel like I should do something.