Have I told my child I’m pregnant too soon?

Hi, after many years of trying and my child begging for a sibling I am finally pregnant. I kept it quiet to begin with but my sister knew and accidentally let it slip to my nephew. I was so worried my nephew would tell my son so we’ve avoided seeing them the past week. Anyway today at 6w4d we seen a heartbeat on the ultrasound and the sonographer said it’s uncommon to have a miscarriage after seeing a nice fast heartbeat at this stage so we decided to tell my son. Now I’m stressing if we told him too early 🙈 when did you tell your children and how was it? (Ps my child is almost 6)