Both Uses

highlight
in
The Glass Castle
(Edited)

And senior year is the highlight of your entire high school experience.
p. 236.4

highlight = best part
It was true that many grown-ups in Welch talked about how senior year in high school was the highlight of their lives.
p. 236.5 *

Definitions:

(1) (highlight as in: highlight the main findings)
emphasize (call attention to something)
(2) (highlight as in: highlights of the year)
something that stands out
(3) (highlight as in: highlights and shadows)
noun: something that is lighter and draws attention -- such as an area of a painting

verb: making something lighter -- such as an area of a painting
(4) (highlight as in: highlights in hair)
noun: a strip of hair that is lighter

verb: making strips of hair lighter
(5) (highlight as in: highlights with a yellow marker)
to mark important text; or something that is marked to draw attention to it -- as with a felt-tip pen with a bright, transparent ink
(6) (highlight as in: highlights the text and deletes)
select (on a computer screen)
(7) (meaning too rare to warrant focus)
The form highlighter, can also refer to a type of makeup that draws attention to parts of the face.