At this point, Futaba is best for you, because her social link will help in battle. Trust me, you'll need to be as ready for battle as you possibly can for December. Though, I will say all that matters is that you romance someone you'd be most likely to romance irl, because you'll get the most satisfaction from that.
Well i was hesitating between Haru and Futaba . And thank your for your answer , i will focus on her social link