To wonder why friend/colleague copies what I say a lot?

[copycatss]

I have a new colleague who I've become friends with, but I've noticed that she will copy what I say and say it back to me almost word-for-word. I'm not sure why, or whether they realise it but it often ends up feeling like I'm having a conversation with myself. It's not just the occasional thing (which I would interpret as us agreeing/having similar views), it's literally everything.

An example was I was talking to her about this difficult project and the conversation went something like:
Me: I'm so glad we both worked on project X before as the experience has been really helpful, otherwise I'd probably be stress crying at my desk
Her: I'm so glad we both worked on project X before this, otherwise I'd literally be crying!

They also try and finish my sentences constantly, as if they're trying to say what I'm going to say before I say it.

They are really nice otherwise, I've just never experienced this level of copying in a conversation before and I'm kind of confused by it

She's probably socially awkward and admires your way of talking. Maybe nervousness, too and trying to be liked. just continue as you are she wont be like this forever

Could also be on the spectrum. masking by copying, they may not realise they are doing it if they have always done it.
I act similar however I'm aware and try not to do it, for me it's peoples mannerisms and accents I start talking the same and I have to try really hard not to.