How does this have anything to do with Y2K? Growing up, Y2K involved our neighbours, who didn't know how technology worked, thinking their computers would come alive once the date hit 01-01-00 at 00:00 and somehow assassinate them during their slumber. Unless, you're trying to replicate the early 2000s anime style in particular. I mean, the outfit is kind of there, it moreso screams "generic party girl" than anything else. As for the overall style, I kind of get what you're trying to go for, but I highly recommend you focus on learning illustration basics like anatomy before attempting stylization. There's an app called Design Doll that allows you to make fully customizable artist models, I highly recommend using it for practice. It's a wonderful tool that can help you get down posing and learn how to illustrate various body types. I also recommend looking up tutorials on how to wrinkles in clothing work. You're getting there, but it looks more like she hasn't ironed her clothes instead of natural wrinkles that flow with the position of the body. The framing and composition is a bit odd as well, the subject would look a lot better centered in the middle of the canvas.
You've got great potential though. Keep practicing and honing your skills. Remember that illustration is also muscle memory as well; your brain knows what a body looks like, but your hands, arms, and wrists don't. You've gotta train the body with the mind. Again, though, keep at it. You're doing great so far and I'd love to see more from you in the future.