So, the character is allegedly born in Sweden and grown up in the US. However, she has some kind of manga-Japanese extreme personality. "Winter" is obviously an English name, not a Swedish name. Also, gender-separated schools don't exist in Sweden, maybe outside extremely religious schools (and Sweden is one of the most atheist countries in the world). It's not likely she'd have gone to one in any country with a Swedish parent.
"Det var så lite" is not a phrase you use unprompted like that, so the context is weird. It sounds arrogant like that, like saying "You're welcome" after "fixing" something no one wanted you to fix. I mean, it's literally just throwing in a wrong language phrase for the sake of having a foreign language phrase.
Drill hair (like braids) is a lot longer than it appears. Getting rid of the drills and ending up with slightly shorter straight hair is a significant haircut. It's also a damn shame. A "scary" appearance doesn't really matter if you approach someone and show them you aren't actually scary. But it might keep others away, for better or worse, depending on what you want.
If you're an extrovert trying to approach an introvert or shy person (there's a difference, contrary to media depiction, and this girls seems to be the latter, not the former), pretending to be an introvert isn't how you do it, since that's just lying and will hurt you later on by setting up false expectations. Just be patient and take it slowly. Both introverts and shy people prefer to not take the first step, so that's mostly left to the extrovert in practice, and there's nothing wrong with that. If it's someone who already likes you you've already succeeded, though, and you can do almost what you want.
I'll see where this goes.