White House daughter of the 1960s-'70s

TRICIA

Nixon’s eldest child shared her first name with a classic Beatles song.

This clue refers to Tricia Nixon, the elder daughter of President Richard Nixon, who lived in the White House during his presidency from 1969 to 1974. The timeframe "1960s-'70s" narrows it down to her, as she was the most prominent first daughter of that era. "White House daughter" is a straightforward hint pointing to a president's child, and "Tricia" is her well-known nickname for Patricia. The answer fits both the historical context and the letter count.