In the last 40 years, this will be only the 3rd new justice ideologically opposite to the justice they replace:
-Clarence Thomas replaced Thurgood Marshall in what has become apparently the black seat.
- While RBG herself succeeded Byron Whizzer White, who was a Kennedy appointment and the only modern example of ideological drift to the Right, as Justice White became a pretty reliable conservative vote, opposed to due process expansion, any limits on policing (including Miranda warnings), was one of two votes along with Rehnquist against Roe v. Wade, and always was pro-business.
Otherwise, center-left Souter was replaced by far-left Sotomeyer and center-right Sandra Day O'C by far-right Scalito (Sam Alito). It's too early to know about Kavanaugh replacing center-right Kennedy.
RBG was the last appointee who was 60 when seated. 3 of the last 5 justices were 50 years old when they started their lifetime term. Roberts, Kagan, Gorsuch.
The oldest this century has been 56, with the definite trend to nominate someone 50-55.