How to date my MMC?

I'm always confused by this and it sort of bothers me that I don't know how to date my miscarriage. My baby stopped developing at 5+4, I found out at 8+3, it was confirmed at 10+3 and I had a D&C at 10+4. So when did I miscarry? Is it when I passed the baby, when I found out the baby had stopped developing or what it when the baby stopped developing? My body continued being pregnant until my D&C, hcg levels and symptoms identical to how they would have been with a healthy pregnancy. Just a bit confused and it's not something I've seen anyone talk about so I have no idea how I'm meant to date it. Any help?