A growth chart isn't a test, where you are striving to get your baby into the 100th percentile. The growth charts show us the statistical distribution of weight, height , etc. in a particular set of babies (or children or adults). So if a baby is in the 50th percentile for weight on the CDC charts, it means that half of the babies of the same age in the US are heavier and half are lighter; if a baby is in the 10th percentile for height, then 90% of babies of the same age in the US are taller and 10% are shorter.