I saw two different Titanic movies when I was a kid, (A Night To Remember, and S.O.S Titanic) and somehow I knew it was based on real events. Raise The Titanic! was published in 1976, and later became a movie in 1980. Pretty sure my Dad had the paperback at the time.
The searches for the wreck before Bob Ballard's expedition were news fodder in the '70's even.
Young or not, you'd have to be in a cave not to have ever seen something on tv or elsewhere about real items recovered from the ship being on tour the past decade or so.
IIRC, there were people back in the 80's about who thought Wings was Paul's first band. ;)