I know that in some countries age of consent is a somewhat floating boundary, some people look like they're 18+ when they're younger and you shouldn't be punished for them deceiving you (that the idea at least).

However it is hard to judge someone's age based on looks alone hence many judges also consider the age of both parties (aka was it an old person seducing 's minor or two young persons in love). In Sweden at least it's 15 no matter how old or young you look ^{^}