Transplant

as it is an autoflower asap... iiam starting my autos in a11l pot filled with slightly fwertilised, fluffy mj growmix tthey love it starting them in small containers may stunt them

Another option would be to up pot it now but leave it in the cup just cut off the bottom. That way you don't have to worry about it getting root bound or possibly damaging a fragile seedling.

Hi, if it's an auto then your gonna want that baby in a bigger pot quite quickly, they generally have a 4 wk veg (as a rule of thumb) and at that point you want plenty of space for them roots to grow, me personally I would do it now but latest the within the next 5 days, hope this helps 👍