My grandma passed away & I haven't cried?

I'm 16 and my grandma just passed away maybe 10 hours ago. I haven't cried.. or even felt devastated. She had very bad dementia & I looked after her when my pop went out & I live on the property next door to them, so we were close. I've never had someone really close to me pass away before. Is it normal to feel so numb? I feel like a horrible person because I don't feel anything.