my baby girl 7.5 months old birth weight 3.5 present weight 6.9 is that normal?? suggest some weight gain foods

A. Hello mom by now that is babies by the age of 4 to 6 months they almost double their birth weight and then it takes about 1 year to triple it, as per the birth weight , the current weight is slightly on the lower side. Give the baby semi solid to soft consistency foods such as by Adding ghee to his meals , also you can give steamed vegetable such as potatoes , sweet potatoes , carrots etc. fruit can be given ,mashed form which are soft in texture such as banana, chikku, etc . Ragi or suji or multigrain porridge, rice and thin dal or Kichidi