She didn't have to say it, but James went ahead and assumed she was going to say no. He had been completely elated that she had returned his kiss, had practically been lifted so high in his excitement. Then, he was starting to come back down, worried he may have gone too far, but holding onto the idea she'd join him for something as simple as tea.
But it was clear to James she didn't want to. It took him a long moment to gather himself up enough to appear not to care, as he said, "Oh, all right. No problem." He mentally kicked himself. He was hurt. "Come on, then."
He lead her out of the shed and back to the castle, the rain letting up a little bit. James felt incredibly awkward walking back to the head dorms, his heart banging furiously in his chest, wishing she'd reconsider. It was just tea, for Merlin's sake! Not a shag party!
But somehow, he knew she wouldn't. Once they were inside the head common room, James began making his way to the door to his room.