I turned 14 in late 1970 but cannot say the 70s were the greatest decade.
I would probably go with the 1960s, 1940s, or even 1930s before the 1970.
1960s: my 1st choice - society changed dramatically going from authoritarian 1950s to the hippie counter culture. Civil rights advances, anti-war movements, free-love, recreational drugs, Stones, Beatles, and the dawn of Zeppelin.
1940s: 2nd choice, WW II and no need to say much more. The impact of the war on millions, the sacrifices and ultimately the defeat of Hitler are historically huge.
1930s: Great Depression after the 1929 stock market crash. Big change from Big Boss ruling class conservatism to Roosevelts New Deal to help the poor and working class.
1970s: started great as an extension to the 1960s but then we transitioned to disco and cocaine addiction. Politics and impact on the culture were not as great as the 1960s.