Hey I have a son that’s a June 2020 baby but this happened with my oldest. He’s a March 2018 baby. The FD alerted me that my sons weight was in the bottom 10 percentile for weight. He was underweight. He’s super picky and won’t try anything new. After he heard the doctor was concerned too he started to eat more. Scaring them into eating isn’t right but he didn’t want to end up in the hospital. So he tried his best and he’s gained a lot of weight. He’s now average weight.
And everytime he tries something new we celebrate lol kinda like potty training but with food!
my June 2020 baby is 22 pounds but she’s a girl! she’s also underweight we have tried everything but she really doesn’t eat much. We started giving her pediasure. I see my daughter with other kids her age and she is way smaller but her dad and I are not big people at all either. she’s also thriving! if your son is thriving, healthy and energetic honestly I have no concern