What's the structure of the second part of this sentence?


> 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](https://www.nhk.or.jp/bunken/summary/kotoba/term/140.html)? (also see
[だ抜き] in [Difference between だと vs と before
認める](https://japanese.stackexchange.com/questions/55990/difference-
between-%E3%81%A0%E3%81%A8-vs-%E3%81%A8-before-%E8%AA%8D%E3%82%81%E3%82%8B) )

