Aesthetic, is basically what you think is beautiful. Everyone has their different aesthetic! It could be flowers in the rain, dancing under the stars and camping in the woods. Or maybe smoke and mirrors, mist, foggy cities. It could be anything you find pleasingly beautiful!
My aesthetic is hard to describe, nothing really fits. But that's what I like about it, everything could be totally different and it still suits you! I would say mine is long walks at midnight, fireflies, fireworks while the sun is out, colored smoke, wet earth, cold water, and pine forests. Oh and flowers, I'm obsessed with flowers.