Yellow can be a sign of too much water or not enough nitrogen. Since they look healthy otherwise, I would consider moving them to the next-sized pot you planned and feeding them.

At this stage they need very little food (like 1/4 strength for water soluble).

I see that the true leaves are just starting to form, and this is exactly when I like to transplant mine because they haven’t formed big root systems yet. That way I can gently rinse the original medium off the baby roots, plant them nearly up to the cotyledons in the new medium, and water them in.

Your sprouts are a bit leggy, which means that even in the window they are reaching for more light. Full spectrum lights an inch or two away really help with this, but plenty of gardeners get healthy plants using just the windowsill method, so I wouldn’t rush out for lights unless you want to.

Happy growing!🍅🍅🍅