Weird Alternate Future Timeline Dream?

This is what I dreamed yesterday:

I dreamt that I had an 3rd older sister who worked as a cop and got brought to my grandparents home from the hospital by her colleagues because she got shot in the leg. It was an birthday of sorts we where all there. My niece Lynn seemed to be 10 years old (she's only a few months old at present) and my sister Pauline was mad at her because she was running around allot. My Aunt and her boyfriend where watching tv with my grandpa. My Grandma was playing Patience as always. My mom was in the kitchen with the fiancée of my sister Tatyana and the boyfriend of my sister Pauline cutting cake and setting tea.

Only tiles

The garden in the back was gone having been replaced by normal street tiles. And It was like I was watching this in 3rd person because I was sitting next to my sister Tatyana in the garden eating cake and toying on the laptop. Which is weird because I remember opening the door and commenting on the ugly danger yellow of the ambulance.

Alternate time line? I am not uncomfortable to say that I did had a chance to have another sibling. But the sibling would have been born after I was and not born before my sister Tatyana. This was like being a Slider... a total wtf dream.