To youngers, casually, 어려 보여.(Eo Ryeo Bo Yeo) 어려 보인다.(Eo Ryeo Bo In Da) politely, 어려 보여요.(Eo Ryeo Bo Yeo Yo) 어려 보이네요.(Eo Ryeo Bo Ee Ne Yo) To elders, casually, 젊어 보여.(Jeol Meo Bo Yeo) 젊어 보인다.(Jeol Meo Bo In Da) politely, 젊어 보여요.(Jeol Meo Bo Yeo Yo) 젊어 보이네요.(Jeol Meo Bo I Ne Yo) 젊어 보이시네요.(Jeol Meo Bo I Si Ne Yo) You can use both for elders and youngers though. To make it clear, 어려 - 어리다 means young but immature 젊어 - 젊다 means young but no matter wheather mature or immature. hope this helped. ok, add to that, u can say 동안 as 'a baby face' it's 童顔 in your language. so you can say : 동안이다. Dong An I Da 동안이시네요. Dong An I Si Ne Yo. you can use the ending of other examples i wrote above. peace.