The music of Newton’s age is Baroque music. Classical music either refers to the whole tradition of Western serious art music (starting approximately with Palestrina and continuing to the current day) or it refers to the period after Baroque.
So “ Baroque” is J.S. Bach, Handel, Charpentier, Purcell etc (1600-1750 ish), “classical” is mozart, J.C. Bach, Hayden etc up to Beethoven (1750ish-1800ish).
Classical mechanics as I was taught it is not to do with the time period,it means “mechanics when you don’t need to worry about relativity or quantum anything “.
As the past recedes, "the golden age" advances in time. "Hollaback Girl" is now a classic oldie.