What I've noticed with dark haired celebrities that go platinum, is that they do it for a short period of time, and then often go back to their natural color. I'd imagine the time to maintain (even if money isn't a factor) is probably the deciding factor.
But it's fun to try a lot of different colors, especially when you are young and if your hair grows pretty quickly, and you are okay with going shorter for awhile if it gets damaged.
It's something I'd definitely only do at a pretty good salon though. I have seen home dye job blondes that didn't really work, and since the process is so intense, there seems to be more danger to your scalp and your hair if there isn't a professional driving. Also you need to decide how you feel about roots growing in, and if you are happy that there will be a period where they are visible between touch ups. That will be a more rock n' roll then ethereal look probably.
ETA: I think the curly blonde look is more 'natural' to my eye, especially with brows closer to your natural color.
Daenerys from Game of Thrones who has hair similar to your first picture with the straight hair, wears a wig, the actress has very dark hair.
