They’re autos.. totally can be done.. but as a first grow - I’d wait until you get to that point to decide. If you have vigorous growth than you probably will be fine topping. If it’s slow, I’d let it ride as is.
Getting to 5 nodes at 3 weeks isn’t a given.
Especially with the variation in ruderalis derived genetics, you’re going to have significant variation between all your plants.
That said - If you’re at 5 nodes by day 21 .. then you’re safe to top in my opinion.
Play it day by day.