Hey G!
Looking great! I personally wouldn't worry about the couple yellowing leaves especially down below where they don't get much light. However, it does seem a little early at day 37. The upper leaves looks good. Maybe a tiny bit of light stress but they should walk it off. Also check if fan blowing too strong? If yellowing leaves happen to be at areas that gets stronger wind, its most likely wind burn.
Otherwise, looks good and ready to surprise you in a few weeks!
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