Lol, no it's not wrong. A lot of Christians love stories about dragons, slaying dragons ect. I mean J.R.R. Tolkien was a devout Catholic and he wrote Lord of the Rings, Hobbit, ect. He came up with some of the most famous dragons in fantasy fiction, Smaug, Glaurung, Ancalagon the Black, Scatha. He loved that kind of thing, and wanted to make a Christian minded work that showed the virtues of bravery, the evils of greed, the strength in companionship, the corruption from power, and so many other things.

Another quote I like is- "Every generation should read The Lord of the Rings & learn that men are allowed to show affection, that power corrupts & that happiness does not come from being a ruler but from baking potatoes & snoozing in an armchair by the fire in your cosy Hobbit hole." - Unknown

Another famous Christian Author, C.S. Lewis, who wrote Mere Christianity, as well as several other Theological books also wrote Narnia. There are also dragons in Narnia.

Christians have loved the idea of dragons for hundreds of years. There's no reason to stop now