I'm 23. I can't stand floral scents or spicy scents like clove, cinnamon. I like fresh, fruity scents and some unisex scents. My favourite FOs are: Love Spell, Avocado & Mint, American Dream (LUSH American Cream dupe), anything minty.
It's difficult because everyone is different, regardless of age, but I do find it common for younger people to dislike floral scents. My partner is 22 and he's a fan of sweet smells like cherry, caramel and marshmallow.