So much of Elle and Noah's relationship is held together by bare interactions — they never open up to one another unless they're in a fight. We can attribute their inability to talk about their feelings to them being emotionally stunted teens, but both Noah and Elle seek solace from other people with no problems. Elle obviously has Lee to talk to, but she also forms a bond with Marco that allows her to talk about things she's afraid to bring up to Noah. And Noah admits that he couldn't talk to his girlfriend about his college woes, so he found a confidante in Chloe instead.
It's easy to blame their young ages for their communication problems, but Elle and Noah have no trouble opening up to other people! At this point, all they're getting from one another is stress and hot makeouts. Don't even get me started on the trust issues their relationship is rife with, especially after Elle cheats on Noah with Marco. Maybe they could learn to talk to one another with time, but I hope the third film has them sitting down to discuss if there's even a relationship worth saving between them. And if there is, they need to talk about how they're going to make that work, whether Elle goes to Harvard or not.