此句是解释first time的从句,相当于It was the first time I'd seen the night face to face in a year and a half,所以其时态参见“was”
是had seen,“It is the first time that I have done sth.”是一种句子结构,这里由于主句用了was,所以从句里的have也要相应改成had
是啊,had seen 不是过去完成时吗