My bb girl was a small size bb when she was first born less than 7lb, but she reached 97% at month 3-4. However, the nurses and the doctors said as long as I'm bf my bb and we don't feed her until she asks for food, it should be ok. Now she is 11 months and it's about 23-24lb and when I look at the new bb chart for bf bb, she is only 95%. I guess bf bb has a wider range in weight.
one more thing is that my bb has never been sick. Even after injection or during teething, her appetite is still the same. That's why her reserve has never really been used. Thank God!