Yellowing will not go away, instead, the leaves will usually die out in favor of new green ones later on. Over watering is the worst thing that any plant can go through, and once its leaves turn yellow, they don't usually go back to any normal green color. Just periodiclly check the soil for moisture or even a slight dampness, and when watering, try to use a very small amount, and meausre what you add. Without knowing the physical size of the pot and the type of soil its in, its very difficult to know how long it will take to dry out some. Here, when I start seedlings, I only water when they start to show signs of drooping due to lack of water. This is usually a much better condition for most young tender plants, that always having 'wet feet'.