Ha! Looking at pictures of me 10 years ago, vs now, and I definitely see a difference.
Probably not that drastic, but this is make believe on a pretend starship. At some point in time we are going to have to pretend. Unless Saavik is completely different?
Point taken with Saavik but that was just really unfortunate they couldn't get Kirstie Alley back for Star Trek 3 or that they couldn't have the actress and character return for Star Trek 6 and instead substituted her with Valeris. I'm sure both movies could have potentially been better with the original actress. Oh well.
Of course, this is one of the many issues you can run into when you try to do prequels. It can be done but takes some impressive casting. For example, Robert De Niro in Godfather Part 2 as a younger version of the Don. If they got that one wrong, the movie would not be considered nearly as great as it is today.