My baby is 4,5 months old but she doesn't like wearing the sun glasses (they left lines on her face! Outch!!!)  I stopped using it right away & wait until she's 1 year old or so... The black sun glasses I bought don't look nicer than cheaper sun glasses I saw at the stores... Besides, the trap around my baby's head made her frustrated (she's hairy so it made her hair messy). I think it would be easier if I bought her the pair of sun glasses that is like the one for adult...