Age range for audition monologues

I am auditioning for waapa next month and i was watching a youtube video where some lady in America who is an apparent theatre expert said "never do a monologue of a character that is outside your age range" i am totally stressing as the audition pieces waapa gave me includes this wonderful monologue (which i have prepared and practiced to death!) which is from the move 'Truly Madly Deeply' about a widow is mourning her late husband' her age is early to mid 40s, i am 24. the piece is very emotive and basically involves her pouring her heart out in a therapy session. does anyone know if there is a hard and fast rule on this age range thing? i dont think the monologue is about a middle aged person so much as it is about a person going through an emotionally traumatic experience therefore i dont think age should matter so much. Please help as i am desperate to find out so i can prepare something else asap if i need to!