Hey man wellcome and well you really got to eat more like alot more do a bit of research with the diet and you will grow like a weed!! trust me
i remember when i started training i was 10 and a half stone 5foot5 i was under eating for about 3months or 3and a half months anround that dropped down to 10stone i was always the big kid growing up (fat) lol strong doe for my age and height. when i brang my kcals up about 500 or 600ish i grew in my first 12 or 13 months i put on 14 pounds naturally!!! i went from 10stone to 11 stone was fat and muscle mostly muscle bodyfat was lower that was over 4 and a half years ago (easyly a bit morethan that) now im 13and a half stone with 2cycles (only did them last year) my point is eat!!!
if you need help theres alot or good pist up in diet and nutrition. i have one heres the link it will give you a good idea on how to eat right
https://www.hypermuscles.com/f68/ski...-gainers-4182/
(im 5.6ish now)
good luck with your goals buddy