I'm a newbie, what to wear?

Hello everyone, I am a 23yo girl and I'm right about to enter the business world. I'm starting an internship on Monday at Mars (the Twix Bounty Snickers and pet food multinational) and I need some advice on what to wear. The day of my interview I looked around for clues on the dress code but I was very confused. Men wore colored jackets and pants with light shirts, some even a suite, and I got the code. But women... The ones over 30, I noticed wide blouses and classic style pants in pale colors, no make-up. But maybe they don't see clients often. I am supposed to work in the trade marketing division, that means I'll be very likely to meet people. They are mainly males, the women work in the high management. They proclaim themselves an informal company, but still it is a multinational company.

My questions are: 1. What are the kinds of business clothes that would work for me?
Chinos and pants in general don't look good on me (flat butt and wide hips), also bright blouses don't suit (I have huge breasts but a narrow waistline). I'm a 2D hourglass Ahah! I feel comfy in tulip dresses and wide skirts, but they don't look professional to me. Also I just can't walk on stilettos. I like high waist skirts and pants, and they look pretty well on me, but I don't know what to wear them with. 2. Is black allowed if office? Like total black, a lot of black? Would you suggest me a few good color combinations that suit an office environment? I attach a pic to help you understand my body type.
Please any suggestion is welcome, this is my very first job ever, and it means the world to me to make a good impression. Thank you everyone