You have the space and right sort of seed for topping. It may be your first time but don't be daunted. There really isn't much to it beyond when to top. When to top is pretty much any time after your third set of full leaves, an inch above a node. The only difference between growing a topped plant and an untopped plant is the number of main colas. Otherwise, light is the same, nutrients are the same. pH, temps, humidity. All the same.
The other side of the coin is, you don't know what you're doing and letting a plant do its thing is a good way to get your feet wet. Even growing naturally, a little LST is usually necessary.