Is it normal to still feel like a kid at 23?
Mostly.Normal for most people
Yes. Plenty of people in their twenties still feel like kids sometimes; feeling grown-up tends to happen gradually, not on your 18th birthday or any other magic date.
At 23, you’re still figuring out who you are and how to handle adult stuff. You can pay bills, make serious decisions, and still feel like you’re winging it half the time. Those things can all be true at once.
People often seem more confident from the outside than they feel on the inside, so it’s easy to think you’re behind. There isn’t one correct age to feel fully grown; most people have moments when they feel capable and moments when they’d like an adultier adult to take over.