The best actor/ actress for the character?

For our film called "The House" we have discussed who is right for the main character of the opening film. We discussed who would be comfortable acting infront of a camera and who could easily portray the character. We have chosen Megan Forster to play the main character (The Ghost) and even though she has no real acting experience we thought we would take the risk and trial run how she is on camera before a few minutes of filming. Usually the casting director would choose a actress with a lot of experience and certainly if the film is a high-budget film, they would choose a well-known award winning actress in the real media world. Megan's acting skills did succeed even though there was a short amount of time to film in and she easily portrayed the character with help of costume and make-up and directing (I gave her directions on how to move and where to move from and to).