My husband, a passionate cyclist, got his first road bike when he was 9 or 10 years old. He rode quite long distances with his dad early on, visiting the grand parents (that would have been 60-70 km round trip) for brunch on Sundays.

He still speaks fondly of his first road bike, a small Bianchi. I know they still make small road bikes. Actually a lot of manufacturers do.

Maybe you can find something used as well, since other kids outgrow their bikes. Ask around in local bike clubs, especially those with more mature members that may have kids the age of yours.

Good luck!