Hi bougainvillier. I love that you are looking to purchase your first VCA piece and only in your 20's. So your smart and have great taste! I am a novice too (but found VCA much later than you). I thought you might like a perspective on how VCA can work for a woman of any decade (I really think the pieces are timeless). You and I have a few things in common - we are just stepping into the world of VCA, I am also petite and again like you I am a more casual person so most days I am understated in my clothing and jewelry.
I bought my first piece just this past Labor Day weekend and my second last week, so it is a slippery and easy slope to travel down.

I bought the vintage alhambra 5 motif mother of pearl bracelet. I bought it because it completely captured my attention. It wasn't what I intended to purchase but it was what I walked out with.

My second piece is the vintage alhambra onyx earrings in yellow gold. I love both pieces but I can see wearing the earrings all the time - with jeans or a little black dress. I wore them yesterday to a football game and I thought it was the perfect accessory. They were completely comfortable - easy to wear all day long. The mother of pearl bracelet captured my heart but the earclips.....they make me do a happy dance.
I guess what I am trying to say is go see everything. Try on whatever your interested in - even what you think you are not interested. The SAs are amazingly helpful and patient. On my second trip I thought I was going to walk out with a pink gold vintage alhambra bracelet - once I put it on I knew immediately it was all wrong for me.
I would not want to be ordering pieces just to see if it might work. Is New York the closest place to actually try anything on without ordering it in advance? Is there a bigger Neiman Marcus closer to you that actually has some pieces in stock? If there isn't, you could make it a really fun day to take the train into New York, go to VCA, have a fabulous lunch, and maybe walk away with your first piece - doing your own happy dance.
I hope you have fun on this journey to find the piece that makes you smile, and hope you will share here when you do.