How does she look on day 11?

You're using peat and coco and you added lemon juice to rainwater? That to me is very bizarre. Coco and peat stuff is already kinda on the acid filler side. And while I don't have an issue with lemon juice really (coz of ascorbic and citric acid), that's also acidic... I would seriously give that thing a good helping of calcium, potassium, some magnesium and a carbon food source.

Jiffy starter + coco is imo garbage, but hey, everyone else disagrees. I'd transplant that to something closer to soil, as I reckon it's beginning to struggle for some nutrients too (calcium and phosphorus particularly).

You seem to have watering/VPD and/or light issues there with the way it's growing. I think your lighting might be excessive or too close or something, dunno, never grown anything indoors.

Hello, it looks green but slow for 11 days in coco and 600w. Coco is meant to be watered frequently because of roots being able to get a lot of O2. It's a light,aerated medium. Watering once a week is kind of rarely watering.Starting in small pots/cups when growing in coco seems waste of time to me as you have almost no chance of overwatering your plant.More space,better root growth in coco.Just transfer it into its final pot and start feeding it. I would water every other day in those conditions (27C and %73). Feed every watering,feed frequently and soon you'll see explosive growth.