my baby is 3 months old and she's only 5.5 kgs right now. should it be considered as underweight?

harshitha
my baby is 3 months old and she's only 5.5 kgs right now. should it be considered as underweight? The only thing that is making me feel good is she poop and give wet diapers as expected. Only her weight is making tensed:( help moms...!!