While I was on the plane home from China, they were playing a movie about a romance between two younger teenagers. The girl was small and had a very distinctive shirt fluffy haircut that framed her face, and the guy  was tan(?). They  first met at the entrance exams? Or something like that, he held out his hand for her to shake but she got distracted and never did. Then he embarrassed her During class by asking to shake her hand again and then she was forced to sit next to him. He also once followed her bus with his bike

Thank you so much 

This is the movie you watched https://mydramalist.com/33694-my-best-summer 

That bus scene was so cute, he figured out that he should take her home instead of sending her off on the bus.

Btw there is also a drama adapted from the same book that movie is adapted from: https://mydramalist.com/16987-with-you  It has even more cute fluffy moments and I love the leads