This passage is from a shopping trip Nora and Vee take. It seems harmless enough. Lots of teens go shopping with friends every day, and plenty of them even go to Victoria's Secret, which is where Nora and Vee are. It's fun to slog through the sales bins and see what you'll find.
But lots of teens also go to shoe stores or try on sunglasses or pick out jeans. The book chooses to put Nora and Vee in a lingerie store, rather than one of these other shop options. It's a reminder that even in a casual, social event with a friend, sex is at the forefront in the book, as is the issue of female sexual objectification.