My first recognition of age setting in was exactly on my 36th birthday. I have no idea why, on this day of all days, I looked in the mirror and realized my face no longer looked young. ↗
I tend to foster drama via bleakness. If I want the reader to feel sympathy for a character, I cleave the character in half, on his birthday. And then it starts raining. And he's made of sugar. ↗