Halloween // insecure sexy costume?

I (24f) really wanna do a sexy costume this year but I'm fairly insecure. I don't think I'm ugly or anything but I have no curves and get mistaken for a teenager a lot and am generally kind of awkward which makes it hard to be comfortable in sexual clothing even when I want to.

I don't really need advice per se, just ideas for something that's sexy, but still maybe low-key. I was a sexy UPS worker last year (the same one Sabrina Carpenter wore in 2022) and that felt pretty comfortable and covered yet still sexy. Anyone know more costumes like that?