I think it's absolutly understandble that you feel this way, this is how YOU grieve and expect things to be handled. But that cannot be said about how other's grieve or what the "right" amount of time to wait is in their book.
I think it's important for others to respect your feelings and to acknowledge that you still feel connected to the property. Rightfully so as so many memories were made there. How does grandma feel?
Is there not a family member that may be able to "buy" the property? This way the house stays in the family and others can keep their "connections". We did this when my grandma passed away;my cousin bought the house and it is now availbe for family get togethers and the like.
However if that is not an option it's best to let grandma make the sole decision. I'm guessing she either lives there or is the executive of the estate? If their are no other relatives involved then grandma has the say. Ask gradma about her feelings, in times like this you get to see all sides of people. Sad, but many people are able to move on rather quickly while others mourn for much longer periods.