I agree with this. Maybe it would help to set some very small goals with her?

Here's a personal example: So I developed some agoraphobia (fear of being outside/among people) during the earlier part of the pandemic. Merely being outside of the house was freaking me out. So my T came up with some gradual steps for me. One being to just open the door and stand there, looking outside. Another to step onto my porch for a minute. One to just go sit in my car without going anywhere. Then to drive around the block, etc. And we celebrated each one.

So for social anxiety, you could come up with similar small goals. Maybe one is, say, calling to make a needed appointment on the phone. Or going and placing a carryout order at a restaurant (or on the phone). Taking a walk where you could potentially run into other people. A brief shopping trip, etc. But small, attainable goals.