First day of class 1 falls in the middle of my client workshop week

Our son starts class 1 on the day school reopens, and I found out today that I'll be at a three-day client workshop that whole week. Most of my workshops get fixed at short notice, but this is a big one that has been on the calendar for weeks, and I'm running the sessions, so swapping isn't realistic. My partner will take him, and relatives nearby have offered to come along. He's excited, not anxious, and has been talking about his new bag for weeks. Logically I know a five year old won't remember who stood at the gate. I'm mostly asking those who missed a first day: did it matter to your child, or only to you?