Legal hier will

Hello Experts,

REFERENCE: "Even when the property is in the possession of a trespasser, she is in its constructive possession; Mangal V. Ratno, AIR 1967 SC 1786.

Father F has a property P, F has 8 children (1,2,3,4,5,6,7 & 8).

F expired without deciding fate of P.

P is in posession of trespasser and suit is pending in court. 

Female child 5 wants to write a WILL for her share in P.

Q. Will this WILL valid ?

Many thanks.