Cool stuff! Isn't being a Dad one of the greatest things?
My boys are 13 and 15 now...both started riding at age 5. For soooo long, any time I saw them in the trails, what I was seeing were some "kids" out riding. This weekend, I stopped to let the boys catch up, and could look back at a section of trail zig zagging through an open area - so I could see them for quite some time without them seeing me. What I saw for the first time this weekend was two "grown up" riders - looking good, good form, riding along at a respectible pace. Kinda one of those moments we as Dads all wait for!
You are gonna have a blast with your kids! Enjoy it!