you may need to tamp down your high hopes a tad. There are perhaps a very small number of people for whom kava would have had a first time effect like what you were hoping for, but far less than 1%, and that would be with grog. Extracts can feel good, for pleasure, but I have never heard of one being used to treat or prevent anxiety.
That is not to say you can’t feel some good effects right away, some relief. But to expect a complete and total effect the first time using an extract, the odds just aren’t even remotely there, except in the fluke or miracle category.
Now, my wife did fix the decades-in-building issues with anxiety she had but it took her 8 months of drinking grog every day before that happened. I’m sure there are others here who fixed or made great strides with anxiety, but i’m guessing it would be hard to find more than one or two for whom it had worked instantly, completely, and the first and every time.
What I would recommend is to start drinking grog every day, at least a shell or two, increasing it if you can tolerate the taste. Look for subtle and gradual effects, like relaxation, feeling of well-being, better sleep, more interesting dreams. Use the extract just for pleasure and really just enjoy it. See how you feel about it after 2 months. You should see some things start to get better after that. It is really more a course of treatment when used therapeutically, rather than a one-shot deal.