Verified answer

Not for creating a will, it isn't. You must only be 18 to create a valid Last Will and Testament in the state of Mississippi.

But the laws of all states can vary. A provision in an out of state will is not necessarily valid in all other states. Some states allow holographic wills and many do not. A holographic will would have no validity in states that do not recognize holographic wills.

Should be valid, yes.