My plant grows slow than others

Not all seeds within the same pack are equally as viable or vigorous. Couple that with your comparing it to other strains entirely, I wouldn’t worry. It may be a runt. It may be slow now and explosive later. I don’t see any indication of overwatering (that’s a good thing you’re doing right) so I can rule that out. I think you will be fine although I understand it’s frustrating when you are looking alongside her and see more growth from the other strains. Good luck