But this is a rueful way to reconstruct Zoey's age and departure.
Isabella-MC: MC still 18, but almost 19 (September).
Rooster Cluck: 6 months ago (March). MC about 18 1/2. Zoey's birthday is around this time (March) and she turns 20.
So MC turned 18 in September. Zoey's (19 1/2) and MC's (18) first sex.
We have a rough idea of how long Zoey and the MC will not see each other. 1 year. We learn this from the EP3 review. So Zoey went to San Diego roughly between September and October. From what we can read in the Zoey Notebook, she had hoped that the MC would visit her after she graduated from high school. But the Rooster Cluck prevented that from happening.