I'm 21. Promise. Here, have a look at my driver's license, my birth certificate, and my kindergarten class picture, which as you can see from all the tiny-tot grunge, is clearly circa 1995. I realize however, I look about fifteen, seventeen tops, which means I'm  carded for R rated movies and hold up the lines at concerts while the bouncers scrutinize my ID like it's one of the clues from National Treasure.

Last fall, after getting my BA, I started interviewing for grown-up jobs. And grown-ups don't shop at Claires or have to get out of the pool to grab their license to prove they can swim without a parent or guardian. So like the girl who piles on so much make-up on a zit she makes it even more noticeable, I overcompensated by dressing like a middle aged nun. Ankle length black skirt, grey crew-neck Tee under a black jacket, some kind of black mule-like monstrosities that may or may not have been orthopedic. The end result was me looking like I'd raided my grandmother's closet, if my grandmother were a super frump.

I needed to find a middle ground, and over the last year I've found some tips that work for me.

1. No Forever 21. I love Forever 21 and a good deal of my wardrobe comes from them. Their stuff is colorful, trendy, and most importantly, cheap. And much as I fought my mother on this point when I was in high school, it looks cheap. For your interview ensemble, at least go to TJMaxx or Marshalls where they'll have discounted brand names. They'll last longer (you'll be doing this grown-up thing for a while) and will make you look a little more professional.

2. Two-inch heels, max. If you live in sky high stilettos, you can probably pull them off at an interview, but otherwise you don't want your nerves to mix with stilts. Nothing says "kid playing dress up" like looking unsteady on her stylish feet.

3. Neutral makeup. Stick with your glitter-less lip gloss paired with natural-looking shadows. And less is more.

4. Add a little color. In order to avoid the nun look, try to incorporate a colored shirt or belt. It won't divert from your aging efforts and it'll temper the severity of an all black outfit.

5. Hold your head up high. So this sounds a little more internal then external, but just sitting up straight, looking someone in the eye, and carrying yourself with confidence will make you look more mature. Think about the creepily precocious child stars who seem wise beyond their year.