Grey DeLisle was 25 in The Grim Adventures of Billy & Mandy: Meet the Reaper when she played the character 'Mandy (voice)'.
That was over 24 years ago in 2000.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 50, and has starred in 199 movies in total, 197 of those since The Grim Adventures of Billy & Mandy: Meet the Reaper was released.
In The Grim Adventures of Billy & Mandy: Meet the Reaper, I think Grey DeLisle looks: