That "Oops, sorry, I just realized" is all implied by that "Correction:". It's more pithy like that. Your parent is not saying "mistake was made", "I was led

That "Oops, sorry, I just realized" is all implied by that "Correction:". It's more pithy like that. Your parent is not saying "mistake was made", "I was led to believe" or what not, which would be passive third-person voice, sneakily trying to shift the blame. Instead, the fact that a mistake was made is clearly communicated through an additional corrective edit. Seems appropriate for a correction of such minor point.