I was the same way when both of my parents died. Despite the fact my mom was not much older than I am now, she had known she had an illness for about 10 years. She had a liver transplant that just didn't go well afterwards. I had prepared myself mentally and actually rehearsed it in my head. I felt a little numb when it actually happened, but I was fine after about a day. The funeral and ensuing shiva was fine and I actually reconnected with some people I hadn't seen in 30+ years. I occasionally miss her and wish that she had seen my kids grow into good adults, but I just never have felt overwrought, like some people describe. My dad was almost 90 when he died. He was sick for about 4 months before this, and I saw him twice in that time, the last being about 3 weeks before he died. We cremated him, so there was no service or anything. My brother and I made this decision, and we both are good with it. His friends all came and visited with him while he was in hospice and said their goodbyes. I know I have a couple of friends here who think I am very cold, but I actually was close with my parents; I just left home at not quite 18, and except for 3 years when we were both in Phoenix, it was a long distance relationship since then. I did see them quite a bit when they moved to San Diego and i was still in AZ, but it was not the day to day thing.
The most grieving I did was when my first baby died after birth, with a genetic condition. But still, I felt I conducted myself well, talked about it, and moved on. My granddaughter here looks just like her, so I have reminders, but with the perspective of almost 36 years, I can smile and imagine what a great person she would have been.