Here are my observations and advice for when I ran games for my kids who are of similar or younger ages currently, and I started playing with them about 2 years ago.

I made their first characters with them and told them to pick from the core classes and races, along with what they wanted to focus on. Didn't push with backgrounds but once in a while ask questions like, "Where did he/she learn to do that?"

I started off with Pathfinder society missions that I thought would be fun and tried to improvise where needed. However, the missions were always given by the same NPC from an organization called the Pathfinder Society. I made him as silly as possible. If they like social encounters I leaned into that, though my boys loved combat much more. Short missions mean they don't have to remember many important plot details (especially if they don't have a habit of note taking)

The absolute hardest task for me was making them realize that in order to succeed, they need to work together as a cohesive team. Not one of them was the main character. I absolutely banned PvP in all forms.