Burden narrates in 1939, but he focalizes through the Jack Burdens from two different time periods, his teenage years in the 1910s and his graduate school experience in 1920.
Thus, while Burden narrates all three statements in 1939, he focalizes the first through who he was in the early 1920s, and the second and third through the Burden who matures in 1938 and leaves Burden's Landing in 1939.
Whereas in sentence (3) Burden narrates in 1939 from his point of view in 1939, in (4), (5), (6), and (7), he narrates in 1939 but focalizes through the Jack Burden of 1936.
He repents not only as a narrator but as the prior self through which he focalizes.
The distinction between voice and focalization clarifies Burden's multiple perspectives: though writing these sentences in 1939, he focalizes through his 1920 frame of mind.