答案：B

本题考查时态。句意：这是我第一次尝到这种月饼。在“It is/was/will be the first time that分句”结构中，当主句动词为is/will be时，that分句动词一律用现在完成体，引导词that可以省略。It is the first time I‘ve been here.Don‘t forget， it’ll be the first time I‘ve spoken in public；当主句动词为was时，that分句动词通常用过去完成体。It was the first time she‘d been at a summer school and she thoroughly enjoyed it。