Jealousy can be a big issue. There could be other students who are interested in either Clary or Jace. For example, a popular girl might have her eyes on Jace, and she tries to break up Clary and Jace's relationship by spreading rumors or causing trouble between them. Also, Clary might have male friends who Jace gets jealous of, thinking they have ulterior motives.
One typical challenge is secrecy. In some fanfictions, their families or certain school groups might not approve of their relationship. So they have to keep it a secret, which is hard when they're in high school and constantly around others.
It would change in many ways. They would go from being carefree high school sweethearts to having a lot of responsibilities. There would be more arguments as the stress of the situation builds up. But at the same time, they would also have deeper moments of love and understanding as they face this huge life change together. Jace might become more overprotective of Clary, and Clary would need Jace's support both emotionally and physically.
Their relationship might start with a simple attraction. Jace notices Clary's unique beauty and Clary is drawn to Jace's confidence.
One possible plot could be that Clary and Jace face a lot of social stigma. Their friends might be shocked and some might even turn their backs on them. They would have to deal with their families' reactions, which could range from disappointment to support. They'd also have to figure out how to continue their education while preparing for a baby.
In fanfiction about Clary and Jace's high school love, their relationship is often complex. It could start with a simple dare. Maybe Jace's friends dare him to ask Clary out, not knowing that he already has a secret crush on her. Clary accepts the date, thinking it's just a joke at first. But during the date, they find out they have so much in common, like their love for a certain type of music that plays in the local coffee shop near the school. This shared interest becomes the foundation of their growing love, as they start to spend more time together, sharing secrets and dreams.
One common theme could be the challenges they face in high school while dealing with the pregnancy. Another might be the reactions of their friends and family. For example, their friends could be either very supportive or judgmental.
It might progress slowly at first. They could start as friends, sharing lunches and talking about their classes. Jace might gradually open up to Clary about his dreams and fears. For instance, he could tell her how he feels pressured to be the best in everything. As time passes, they become closer, and their friendship starts to turn into something more, like when they hold hands for the first time during a school event.
One cute moment could be when Jace gives Clary his jacket during a cold high school football game. It shows his protectiveness towards her.
In high school, their love could face the challenge of time management. They both have their own Pokemon training schedules. Ash might have early morning battle practice, and Dawn could be busy with her coordinating rehearsals in the evenings. Finding time to be together would be tough. Also, peer pressure could be an issue. If some of their classmates don't approve of their relationship, it could make things difficult. For instance, if there are some students who think Ash should be with someone more like him, a battle - focused girl, or vice versa for Dawn, it could put a strain on their relationship.
One challenge could be Inuyasha's jealousy. He might get jealous easily if other guys show interest in Kagome. Also, Kagome's busy school schedule with exams and extracurricular activities could put a strain on their relationship. Another issue might be Inuyasha's past, which could make him hesitant to fully commit to a high school romance.
One challenge is parental approval. Parents may not want their kids to be in a relationship during high school as they think it might affect grades. Another is time management. High school students are busy with studies, clubs and sports. Balancing a relationship with all these can be tough. Also, peer pressure can be an issue. Some peers might make fun of the relationship or try to break it up.