You don't have to top it if you don't want to. Not everyone does, so if you do not feel comfortable I wouldn't do it. Nothing wrong with it either way.
I would just recommend letting the plant get a little taller/stronger before training. I prefer to let it get 5 or 6 nodes before any training. YMMV and all that. I just feel that when I have started the LST sooner, it can stunt the plant. There's really not a lot of benefit to bending and such so soon as there is nothing really on the plant yet. If you let it get a little taller and beefier, I find the LST doesn't really affect it much at that point.
On the flipside, I have started bending and tying very soon and it can stress the plant a bit more than I like and slow it down. If you have a couple plants, try it both ways. See what works best for you.