Can I top this one?

Hi

I have a plant going 12/12 from seed under a 250w hps. It's around 2~3 weeks old, and I was wondering whether I could top it now since it has 4 nodes on the main stem now.

Pics are in my link if you need to see them. It's the plant next to my bigger afghan plant

Thanks!

You can but you may hurt your yield. Topping and pruning to improve yield should really be done before 12/12.