Why is this Nicole Kush so slow? 😔

Hi guys, I planted my first photoperiod plant. Seed bank unknown, it was a gift (≈3-year-old seed). Setup: SF1000 at 80%, 24°C on / 20°C off, RH 65%, Lightmix + 5% perlite, transplanted recently into an 11L pot. After 4 weeks it’s very slow. I did LST yesterday but removed it