I am 18 years old and stand about 52 in height. Height alone makes it difficult to find jeans. In addition, I weigh around 105 pounds, which makes it next to impossible to find jeans that actually fit, because I am a size 3 but if they fit in the waist they are tight in the bottom (rear-end) and upper thighs. Its especially around the waist that I have problems; I alway find that there is a gap at the back of the jeans, making it so I always have to wear a belt.
One day while shopping I stumbled into a store called Marshals, at the Mall of America. This store has name brands for discounted prices. I grabbed a few brands to try on, and the first few ones I tried on I found the same problem. I finally got to the last pair, which was the Calvin Klien brand. Normal price on these are around $50-$100 US Dollars. I tried them on and they fit perfectly. I was with my boyfriend and I walked out of the dressing room to show him and I walked out, slowly turned around, and before I could ask him what he thought, he said he was buying them for me. There were no large gaps around the waist, the rear-end and thigh area were not tight (nor too baggy) just roomy and perfect. The crotch also was button up which I like becuase then the zipper doesnt stick out all the time, and you dont have to worry about your zipper falling down once the jeans get older.
I suggest if you have a clearance/bargain store near you, go in and try on the more expensive brands. Chances are, because they cost more-they will be better made.