Thinking back, I may have been interested in her since she (Akane) first introduced me to her. When I found out that today was her sister's (Mayu's) birthday, I couldn't sit still, and before I knew it, I was in front of her house. I rang the doorbell and was planning to go home if there was no response, but her sister came out. Ah, I really do like her. My feelings turned into certainty.