Looks really good man, you should be proud for a first grow. Looks happy and healthy, especially for being less than a month old from seed.
As far as topping goes, once your in flower you should really be doing anything like that to your plant. Not that it can't be done, but it will stress out the plant and divert energy from making buds to recovering from the topping. I'd wait till your next round to mess around with topping or FIM('fuck I missed') or supercropping etc. All these techniques should be used in the veg state and done soon enough to recover fully before flowering.
Look around the forums and do some research about the different techniques of training your plant. Not everyone does it and every strain is different. One strain might LOVE to be topped and reward you with an increase in yeild for doing so. Another strain might hate you for topping her and either recover very slowly or actually decrease your yeild. Only time and experiment will let you know for sure, but that is half the fun of growing!
Hope this helps, like I said, everything is looking good-keep it up.