Renai Daabii

From Shoujo Crusade:

Miki always loves to be the first in everything. She now aims to be the Seiryou Miss of the school Christmas party. She plans to confess to the school's prince, Suga-senpai, when she's chosen and be his first girlfriend. However, her guy friend, Yuuma, who has always supported her, opposes her this time. Why?