Six is the age most riders stop pushing along and start trying things. This collection covers that shift: scooters built to take a drop, plus skateboards for riders heading a different way.
A pro scooter is a fixed height, so it is chosen by rider height rather than adjusted. The Carve Pro-X at $69.99 and the MG2 Obsidian at $89.99 are the two smallest, suiting riders from about 3'6". Both run 100mm wheels on an extruded aluminum deck with a steel T-bar. The bars may sit a little above the navel at six, which is normal, and they grow into it within months.
If they are drawn to a board instead, the 22-inch Locker Board is $19.99 and short enough to control at this age. The 31-inch decks are a size up and better suited from around eight.
Not every ride is about tricks. The folding scooters here handle the school run and fold small enough to carry when they lose interest halfway home.
If they want to jump, kerb-drop and get to a skatepark, take the pro scooter. If they want to cruise and mess about with friends, a board or a folding scooter will get more use. Either way, buy for the size they are now.