Give your tank another 5 or 6 months to settle in and mature before adding an Anemone. It's unfortunately not something you can test for. If your cycle has completed and water quality is good, you can start with a fish or two, even hardy frags. You should be able to find a local to set you up with a piece of leather, some Xenia, or Kenya tree. If they do well, it's a sign that you're off to a good start.