my baby is just 8 month 2 days old her birth weight was 2.5 and now she was 6.6 kg weight is that ok

A. If I just go by the birth rate and the concept that your child should be at least 4 kg more than the birth weight then this is good enough as of now but on an average on it this is quite less of course of increments over the period to look for a diet which will help in increasing weight