Cystic hygroma - do I get an amnio?

At my 12 week scan they found “bilateral symmetrical cystic structures” on Baby’s neck which they said was a small cystic hygroma (didn’t give me a measurement) with “subtle subcutaneous edema.” I was referred to MFM and a genetic counselor. We met with the genetic counselor last week who said they’re not concerned with anything in our family history. (My husband has 2 nephews with chromosome differences but they are spontaneous changes with no hereditary risk.) They said things they would be concerned about with the hygroma are Noonan syndrome or a congenital heart defect. Blood test was low risk for trisomy 21/18/13, monosomy x, triploidy, 22q11.2 deletion syndrome. I’m 15 weeks now and we have an early anatomy scan scheduled for 17 weeks. They’re going to schedule a fetal echocardiogram around 20 weeks. They offered us an amniocentesis if we want, and I’m unsure if this is something we should pursue given the information we have available. Is the risk of the amnio worth it? Should we wait until the 17w anatomy scan to decide based on those findings? I’m really on the fence and would love to hear others’ experiences with cystic hygromas and amnios.