人と話すだけでも緊張するのに、それが年上の女性とくればなおさらだ
Here I think それ refers to 話し相手 and the second part is made from these 2 sentences:
それが年上の女性とくる
なおさらだ（no subject）
And then the particle ば is used to connnect the two sentences and makes them the second part of the original sentence. Is my understanding right?
If so, in sentence それが年上の女性とくる, what's the structure?
Is it
[それが][年上の女性と][くる]
where くる is the predicate(述語) of それ(subject)? Or it's
[それが年上の女性(だ)]とくる
where it omitted だ and it's a だ抜き? (also see [だ抜き] in Difference between だと vs と before 認める )
