Hello Friend, the site you referenced is a seed bank that carries roughly 5-6 Auto OG Kush strains. I'm guessing you went with "Kera Seeds" as they had one of the cheapest and highest rated OGK strains. Regardless buddy, it (OGK)is listed as a 70 - 80 day Auto (so give it 90 days)- and they are listed to grow to 90 - 120cm (35 - 47inches).
Looking at your plant, if you switch up a few variables I think you can fully expect it to get a nice early to mid-flower stretch and pound on some bud. There is concern though, to me the color of your plants leaves indicate a Nitrogen deficiency. Might as well hook it up with some P and K while your at it - and is there any way possible you can switch your light because MH is fantastic for Veg but it's a less than ideal spectrum for Flower, and the Spectrum you provide directly impacts your plants ability to grow and uptake nutrients. Can you get yourself an HPS bulb and some Nutes ? What kinda nutes are you using if any ? I see you have some Perlite mixed in, anything else in the mix ?