It could become more complex. As adults, they have different responsibilities and experiences. Their relationship might start off a bit strained as they try to fit into each other's new lives. But eventually, they could find a new level of understanding and respect for each other.
The relationship will likely grow stronger. They'll have to rely on each other more for daily tasks and support. For example, if Percy has a bad day at work or school, Annabeth will be there to comfort him right away, and vice versa. However, it could also be a bit strained at times. There might be moments when they feel suffocated by each other's presence, but they'll have to work through those feelings to keep their relationship healthy.
When Annabeth is mad, Percy will likely try to make it up to her. He might start doing all kinds of things like bringing her favorite foods, trying to help her with her projects. But Annabeth might not be so easily swayed. She'll be looking for a real apology and for Percy to show that he's learned his lesson. So the relationship becomes a bit of a power struggle, with Percy trying to regain her favor and Annabeth deciding whether he's worthy of it.
It could become more professional. They might keep their personal feelings aside and just focus on getting the job done.
It could develop quickly. They might immediately start planning their next adventure together.
At first, it could be a bit rocky. Percy might think Annabeth is too uptight, and Annabeth might think Percy is too carefree. But as they spend more time together in the high school environment, perhaps during lunch breaks or in after - school clubs, they start to see the good in each other. For example, Percy might notice how Annabeth always stands up for what's right in class debates, and Annabeth might see Percy's loyalty to his friends.
Their relationship could become more intense. The hickeys might be a sign that they are moving to a more physical and passionate stage. Percy might become more protective of Annabeth as well, seeing how she's so openly showing her affection in this way.
Their relationship could become more intense. With her hearing his thoughts, they'd be more in tune with each other's feelings. It might make their bond stronger as they'd understand each other on a deeper level.
It could develop into a deeper friendship at first. They might study together and support each other in their college pursuits.
It could be that they face some challenges in their relationship upon meeting again. Maybe there are misunderstandings or new characters that cause some jealousy or friction. However, through communication and their shared experiences, they would work through these issues and come out with an even deeper bond.
Well, it completely shatters their trust. Percy would be devastated and feel extremely betrayed. He would question all their past interactions and wonder if Annabeth ever really cared about him.