4 months Baby girl weight

My baby girl is 4months old exclusively breastfed and she weights 6.05kgs(13.33lbs). Her birth weight was 3.25kgs(7.16lbs) she looks tall and a bit thin. Her pediatrician said she is in good weight growth, but my in-laws always keeps on saying that she is very thin and maybe my milk is not enough for her. This is always making me very depressive. I am pretty sure that i have enough milk supply.

Can someone tell me if her weight growth is good or she should grow more. How is your babies growth?