Hi u v very good height. U can gain weight but consistent way. eat high calorie diet in break fast,lunch even dinner. that means more basmati rice/ rice products, add fibre rich like whole wheat ,multi grains chapati, home made alu porotha,. also every meal need to add good quality high protien like egg,fish,paneer, cheese, yogurts, curd,. in meals add 2 tsf ghee or some time butter in breads. oat, porridge, Dalia, max vegetables, fruits like banana, grapes, mangoes, coconut more.add dry fruits ,nuts also. almnond, cashewnut etc. mostly sleep min 8 hrs & no stress,.