I agree with those that have suggested she finish out the year. She is doing extremely well academically and perhaps given the additional time, things might fall in place socially. Also expectations have to be managed - having one or two friends might just have to suffice for now. But I do think finishing the year will look better on a transfer application and she can then say she gave the school a chance.
There is certainly no shame in a transfer, many students do so every year. Things aren’t working well, you make changes. That’s just life - whether it’s college, a job or a relationship.