Possible Clues:

• Von Trapp girl who's 'sixteen going on seventeen'
• Oldest von Trapp child in 'The Sound of Music'
• "The Sound of Music" teenager
• Rolf's duet partner in 'Sixteen Going on Seventeen'
• One of the von Trapps
• Von Trapp girl who sings "Sixteen Going on Seventeen" with Rolf
• Von Trapp daughter in 'The Sound of Music'
• “The Sound of Music” role
• Eldest von Trapp sister
• Eldest von Trapp daughter in 'The Sound of Music'