Katsuki and Izuku are married and are both 24 years old.

”Babe?” Izuku's whispering voice stilled Katsuki's from dozing off to sleep entirely. ”Where's the baby?..” Izuku asked,his expression a mix of concern and worry.

Katsuki looked at him,still half asleep. ”..What do you mean-?” He said disoriently.

”Where's Shizuku?” Izuku repeated in a hushed tone.

”I don't know,” Katsuki grunted sleepily,knowing damn well Shizuki was sleeping beside him.

”Where's the bab—” As Izuku said so,he pulled the blanket off Katsuki,revealing Shizuki cozy in his arms.

”Kacchan...” Izuku said with a sigh.

”Babeee..—” Katsuki huffed.

”We said she's going to sleep in her big girl bed, that's why we bought it.” Izuku whispered.

”One more night, please..— she's growing up too fast,” Katsuki retorted jokingly.

Izuku almost snickered. ”She needs to go to bed..”

”So do i, so go to sleep..” Katsuki retorted, before adding: ”Don't wake her up..” He was already closing his eyes.

Noticing this, Izuku insisted again: ”Okay, let me take her to bed.”

”No..out!.” Katsuki whispered back sleepily, enjoying their little back-and-forth bickering.