Re: Intestate- Again
Despite all the detail you provide, there are still some missing pieces here. I am guessing that your grandparents were also residents of PA at their death? If so, then the key part of this question may be decided by PA law, not Virginia law. Inheritance rights are governed by the state of "domicile" at death. I am not a PA lawyer.
If they died as domiciliaries of Virginia, I again assume from the subject line of your question that the grandparents did NOT have ANY will. Assuming that your grandparents did not have any children from a previous marriage, than in 1946 the land became owned by the still-living grandparent 100%. In 1952, when that second grandparent died, the 6 children AND ANY OTHER CHILDREN WHO DIED PREVIOUSLY owned the land in equal shares, PER STIRPES.
All of the children would own all 27 acres in a pool of sorts.
When each of the (6?) children living in 1952 died, the ownership of each child's share would be decided by THAT CHILD'S OWN WILL, if any, SUBJECT TO THE LAWS OF WHATEVER STATE the child lived in at his or her death.
You say that one child's widow takes that child's share. Maybe.
You say that the last child of your grandparents who died last year, who was your Aunt, in fact HAD A WILL. That will can only give your cousin what the aunt who died last year actually owned AT HER DEATH. Your Aunt could have written a will saying that your cousin gets the White House in Washington, but that would have no effect unless your Aunt actually OWNED the White House in Washington. I say that to make a point, but your Aunt could not give 100% of the 27 acres to your cousin unless your Aunt actually OWNED 100% of the 27 acres... which I highly doubt under the facts you present.
Your Aunt's will can only give what your Aunt owned, nothing more.
Since it appears to me that your Aunt only owned 1/6th of the 27 acres, the most that your Aunt could give to your cousin is 1/6th of the 27 acres... nothing more.
NOW IT IS IMPORTANT TO SEE IF THE DEED ITSELF CONTAINS ANY INSTRUCTIONS ABOUT OWNERSHIP, such as joint tenants with the right of survivorship. I highly doubt it. BUT YOU WOULD HAVE TO READ THE DEED to make sure it does not discuss "joint tenancy with right of survivorship" among the grandparent's children (which would be highly unusual, but not impossible).
However, to claim a part of the land as a grandchild of the previous grandparents, you WILL need to prove that you are one of the grandchildren.
But, if you have a birth certificate, and you get it properly authenticated from the city where it was issued, then it really does not matter what your cousin or anyone else says. Absent some extraordinary proof to the contrary, the birth certificate WILL BE PRESUMED TO BE CORRECT and conclusive.
I AM VERY CONCERNED ABOUT WHAT HAS BEEN HAPPENING WITH THIS LAND SINCE 1952 AND I WOULD URGE YOU TO DISCUSS THIS WITH A LAWYER.