It's canon, but just like Rebirth, the current timeline is only constructed by bits and pieces mentioned in the current story or flashbacks, and that's before getting to which part is current continuity, and which part is them remembering previous continuities.
I tend to count everything as current continuity unless it clearly contradicts something.
So as far as I know the current timeline goes like this
- Altuum's forces cleared out Themyscira
- The Amazons moved in
- Diana was crafted from clay and Nubia reborn out of Well of Souls
- Diana's childhood stories
- Donna Troy was born (details I don't know)
- Diana moved to man's world
- Batman/Superman World's Finest with 16-17 year old Dick and Kara (age unknown)
- 12 years ago Jon Kent was born
- Barry's Death in the current continuity's equivalent of Crisis on Infinite Earths that doesn't destroy the Multiverse (Kara's death status is unknown)
- Wally became Flash, Jason Todd died, Tim Drake became Robin
- Hippolyta beheaded Echidna
- Tim, Cassie, Kon and Bart formed Young Justice
- Infinite Crisis (Max Lord's death status I don't know)
- Final Crisis
- Rebirth stories of Artemis
- Infinite Frontier (a bunch of people are resurrected from the dead)
- Current story (Kara and Dick's age is unknown, but Dick is at least 29-30)
Jon is supposed to be born after Death of Superman, but that can't be because he was born 12 years ago. Everyone would be too old. So someone, either him or Dick (they were talking about it) remember things wrong, remember the chronology wrong, or remember things from past continuity instead of the current one.