Anyone shopped at Rue 21 before?

Is it more for teens and young girls, or would a 23 year old be able to find stuff there. I'm really really thin and I can't find stuff that fits, and I heard their sizes run small. Most size 0's are too big, do they sell 0 or 00? I found their website and the clothes look cute, but it didn't give any info about sizes. Just any info would help, thanks.