“You’re too old for that.”
Is really a shitty concept. You’re too old for everything. Cartoons, sleepovers, candy, etc. Basically, you’re too old for fun. You shouldn’t be too old for fun ever in your life. If you want to watch cartoons, do it! If you want to have sleepovers, do it!
CS Lewis famously said that the intrusive desire to appear grown up all costs was in of itself a childish trait that secure adults should’ve grown out of it.
He worded it that “When I was young I hid my love of fairy tails for fear of ridicule, now that I’m 50 I read them openly”