Her graduation announcement was pretty sudden, but her reasons are sound and she's clearly thought about it for some time. She was one of the primary sources of both talent and cuteness in the new generation of H!P. Even if Yuuka the idol retires, I'll continue to support Yuuka the person, who has shown her courage and resolve.
You're welcome! If she decides to get back into show business after university, we will. Or if she gets a personal Twitter or something. But it might be a case of Eri Kamei, since she's retiring to a normal life...