Hatsukoi wa Nido Oishii

Mikumo Higashino and Sei Imajo were once close childhood friends. Then they grew apart when Mikumo had to move away for her parents' work. Two years have passed, and through intense studying, Mikumo makes it into same prestigious high school as Sei. However, Mikumo's heart-pounding excitement turns to surprise when she finds out that Sei isn't who he used to be! A sweet, innocent romance that will be sure to give the reader butterflies in their stomach!

(Source: MangaPlaza)