Sorry to be the bearer of bad news, but the fonts on their own indicate it's a counterfeit. Also, from the picture, the card looks like it has no texture to it. Rainbow rares from the early Sun & Moon era sets like Crimson Invasion have texture to them.
What store and what product type did you buy it in? Wal-Mart and Target both stock some unofficial boxes of cards and packs that are not packed by The Pokemon Company and are instead assembled by a different company that doesn't check the cards to filter out counterfeits before they pack them.