I didn't top mine, I used the supercropping method
if you don't know what that is, its basically when you pinch your plants stems until you hear a slight pop and then leave it to heal itself. It will, if it survives (which it should), grow stronger and have thicker stems. I did this to my main stem when my plants were at around 3-4 weeks. Then, as they matured, I continued to do it to the future bud site stems and now all of them are very thick and strong. Hopefully, this will make my plant able to hold up some heavy, nice ass buds