Fair points.
I know it is story so I have to suspend disbelief but it does feel that she was away a lot longer than it took to discover she didn't like surfing. Must take at least a year to cover your body in ink and for it to heal fully. Were there not closer places to learn how to surf - away for a few weeks, find it is not for you, get it out of your system and come back.
And I get the Grandma honour thing, but against the life long companion and love, there didn't seem to be that much dilemma.
But all your points are fair, it is just a story - to be fair my major issue is that she came back covered in ink - but that's just me, others and the MC may love that.
Im the opposite too, i really like zoey, shes prob my 3. fav after Sage and Josy at this point and i would pick her over Riona any day with closed eyes. Wont discuss the tattoos as thats just a matter of taste and preference.
But i feel youre not judging her fair when youre saying she left her lifelong companion. The money sounded more like an excuse she made for herself, convincing herself its better to go back home without accounting why she wants to go back home fully.
But its not that Tremolo or she had anything figured out at this moment, neither of them was aware what their relationship is and what they are for each others, just two confused teenagers not able to define their feelings and relationship. Zoey seemed to be rather depressed too.
They didnt made any plans to marry or even considered each other girlfriend/boyfriend, Tremolo didnt asked her to stay, he just sat their at the train station like a little bitch and said nothing at all. He didnt even tried to convince her to stay for a future together, only when she was gone he took the time to think about it (and suffer) and realise what he was missing.
Same with Zoey, it just took her longer which is reasonable as she had a lot of new experiences and influences. But when San Diego became normal and nothing new anymore she took the time to think too and had the relevation but still is kinda trying to blindsight herself. "Home sickness" was again Zoey lying to herself, afraid of her own feelings or the possible loss going along with it.
I think she supressed a lot of her feelings since her grandma died in general and is just now ready to really live again.
And even when not chosing her again and staying friends with her, she improves the story imo, showcasing how every decision can have a huge impact. If Zoey wouldnt have left, the whole Tremolo at college success-story would have never happened the way it happened.
In a way it was nessecary for Zoey to leave to give Tremolo the possibility to become the man Zoey always envisaged him to become:
And lets be honest, she groomed him to become "the Conqueror" lol