This is what we found on Wikipedia regarding the When I Grow Up:

"When I Grow Up (To Be a Man)" is a song by American rock band the Beach Boys from their 1965 album The Beach Boys Today!. Written by Brian Wilson and Mike Love, it was first issued as a single on August 24, 1964, paired with the B-side "She Knows Me Too Well". It peaked at number 9 in the U.S., number 27 in the UK, and number 1 in Canada.

The lyrics describe a boy who is feeling anxious about his own future when he will no longer be a teenager, pondering such questions as "Will I love my wife for the rest of my life?" It is possibly the earliest U.S. top 40 song to contain the expression "turn on", and is one of the earliest rock songs to cover the topic of impending adulthood. Musically, the song has been highlighted for its jazz influence and unique arrangement and harmonic structure.