Is it normal my 6 week old isn't smiling yet?

Hayley • ~IT'S A GIRL!! 💕baby # 2 due May/June 2019~ 💙William Jack 17-08-17 💙

He still does the newborn reflex smile in his sleep after food sometimes but nothing else. He is becoming more expressive but mostly just looks confused or mad, no cute baby smile yet haha. I read somewhere that they should have their first real smile around 6 weeks?