It wasn't the first time that Orange County threw weird stuff at the people who Dreamed. Stefan was a vampire. Damon was a vampire. They had these batshit crazy Dreams that gave them gifts, memories, and turned them into supernatural creatures. Not to mention all the other crazy stuff that happened around the county, like monsters attacking, Halloween decorations coming to life, and mistletoe kidnapping people until they kissed. What more would a little de-aging hurt?
In all of this crazy, Stefan was taking care of his older-younger brother, and the younger-younger Elena. It wasn't too bad, though. He was getting to spoil them with fun trips and ice cream and everything.
Stefan chuckled. "We can absolutely get some ice cream. I think an ice cream truck passes by this park."