I'd say she is normal for a year old but small for a two year old, chances are pet store fed her the same size meals for most of her life instead of gradually increasing size. Feeding at every two weeks she would be larger, even if she came from "small" parents. With proper feeding you should see some nice growth in the next 6 months-year and even more when you get her on larger prey, she will start to get the girth on her when she hits the 10-12 ft range. Be prepared and have fun, congrats on the new beauty.

P.S Newspaper under the aspen will help save the bottom of your cage and make cleanup easier, your not messing with small BP turds anymore