I know only because I volunteer in AP CS classrooms. Linked Lists are covered fairly early in the course. Doubly linked list insertion is one of the standard reversed classroom (?) labs in one of those teacher's courses (but not others; we spent more time on trees in one class and one of the teachers was quite bad and spent a hilarious quantity of time on String.format). In the DLL lab the kids do just fine in an hour or so. They do not see DLLs before that but it is the final lab of the linked lists section.

My high school did not offer CS except as an independent study (you could technically do anything as an independent study, so "offer" is shorthand for "convince a teacher to let you sit in their classroom during planning period and find a way to sit for the AP CS exam").

There have existed high school CS courses since the 80s. (The AP CS exam was introduced in 1984.)