With respect, more than likely. I'm guessing that you had quite a deep relationship with your grandmother and that there's a whole lot of Love in your family circle. If that's the case it's quite natural for you to want your grandmother back, to keep her in your heart - which is what you may well be doing here. Give yourself time to process because that could be clouding your thoughts, especially if you're coming from a perspective of loss, emptiness...... Gone doesn't mean gone, gone just means that your grandmother has another Path to walk, and if she's moved on then she's completed her Life's Purpose. Let her go, because if you don't you'll only hold her back. The ties of Love are the most powerful.

It's been said that there needs to be three generations to pass before reincarnation can occur, but then it's happened in less time so how much time it actually takes is up for grabs.

I would think that your grandmother is one of your Soul Group, if so then you'll see her again. Have patience, wish her well and let her move on.