my baby's birth weight is 900grams ,(delivered in 26 th week )now he is 3400 grams, is it an idle weight for him, and giving breast feeding only

A. Your child was so much premature your child is gaining very well like a full term child so they can be no complaints about the growth and weight of your child initially yes it was very less when the child took birth as of now it is very good so looking at the stats that you have provided I can tell you that the child is taking very proper growth