Open heart surgery

I just got the go ahead to schedule open heart surgery for my 4 month old daughter. Idk how to feel. How will I get through this? I have a month or two to get myself together but idk how. I’m trying so hard not to stress. She’s a fighter, she has been since day 1. I just know in my heart she will be okay, but there is so much unknown. How do I stop the what if’s in my head? How do I go about my daily life know what we have ahead of us? Has anyone been through this? I feel lost. I hate that I can’t stop this. I hate that she has to go through this. I wish I could do this for her but I can’t. As her mom I can’t fix this for her and that’s kills me.