Help!

Today will be my 30 month old Ped check up! My lo had a 2 year old blood work and her iron came back low. Changed up her diet and all went back again for blood work her blood work came back normal was 11 something for iron, Ped said she wanted to check again since she saw the extra storage for iron was low but I think 11 isn’t bad number and I really don’t want to get her checked again, but I been going back to doc office since my little girl has the same Ped, she been asking me if the blood work has been done I been keep on changing it and moving it around, blood work and toddler is traumatic, hard to find vein this and that…. What can I do how do I avoid this blood work again! Idk I mean should I just go ahead with the blood work again?