Unsure on a third

My husband and I have started talking about having a third child and I feel so uncertain. I don’t feel done but the idea of three is a bit scary and overwhelming. I have a 3.5 year old and a 1 year old who has had two open heart surgeries and spent 6 months in hospital after birth (we had no idea anything was wrong during pregnancy). She has a genetic condition but is doing really well now. I am SCARED! But I don’t want to let fear stop me from growing our family. I also worry about lifestyle with three in terms of taking big family trips, etc. I would love feedback, your experiences, etc!