I've never been given that advice in any of my art classes. Over-detailing things is generally frowned upon. I'd be curious to know where they're getting that advice from. It might not be school advice as much as it might just be artists following general trends in other movies. Slowly but surely the over-detailed look seems to be fading out, which I'm happy about. For a while everything kind of had that look. From what I understand, it's not illegal for an 18 year-old to date a 16 year-old. The Romeo and Juliet law was a thing because Shane and Tessa were 'doing more', if you get my meaning. It's creepy if there's a bigger age difference between the adult and the teenager they're dating, but I don't think this relationship will come across as creepy. Since Charlie is just turning 18, there's probably only about a year difference between them. The new Spider-Man (who's 15) tried to date a senior who was probably 18, and no one found that creepy.