Detours before Love

"I got back together with Gen," Peter tells Lara Jean on the Lacrosse field when she comes to profess her love. She understands she needs to move on. The same night, Lara Jean receives a letter from an old friend. This might a sign. Unless it isn't? This picks up at the end of the first movie, let's see how Lara Jean and Peter get back to each other, if they do at all.