My 3 month baby girl has gained only 100 gm in 3rd month.is it okay

A. Yes it is normal, At this stage, your baby will start to move away from a steady gain of about 6 ounces per week to a little less than 4 ounces. This means that she will gain roughly 2 pounds this month, and every month following until seven months old. Baby Should Eat: Breast milk or formula.