My middle child had an umbilical hernia. We were told to wait and watch to see if it heals. At 5 months old I took her to a surgeon at Childrens. He said the same thing but to bring her back in 6 months and they would measure it again. At the 6 month return trip they discovered it had actually gotten bigger. We had the surgery at Childrens and all is great. They let me stay with her until she was asleeep and be the one holding her when she woke up. She didn't have any problems other than sleepy for a day or so. If you look really close she has a small "smile" like scar under her belly button. It is so faint that she will get to enjoy bathing suits without worry.
My suggestion is to just keep a watchful eye on it and if you feel it needs to be checked. Have it checked. My ped dr was less than thrilled that I took her in but after the surgery he realized that "mom was right".
I pray that this is the most you will go through with your sweet little girl.