If it were mine, I would wait. You really don't have anything there yet to "LST". Reading through previous answers ....
@00110001001001111O has given you the best answer. I would not do anything to your plant(s) without having a plan first.
I use a lot of LST and even super-croping to fit my plants into my space. I wait for my plants to get about a foot tall and then I start by tying down the main stem. This causes your side branches to go through somewhat of a growth spurt and bushes out your plants. After a few days, I will untie the main stem and allow it to grow normally for another few days before I decide if I need to tie the main stem down again. Once you have a short bushy plant with somewhat long side branches, you can begin your LST or weave it through a scrog net.
If you're growing autoflowers, don't top it. You'll lose a significant part of your yield. Simply stay with LST & super-cropping or run it through a scrog net.
If you're growing photoperiod plants, it's up to you if you want to top it ... but wait until at least the 5th node. Right now is too soon for the reason stated by
@00110001001001111O