Re: In this picture it looks like the white feathers are starting to grow on the eaglet's head, or is it too soon for that?
A juvenile Bald Eagle does have a few scattered white feathers on its body, mostly on the breast, and also has white under its tail and wings (especially the "armpits"). Light tan and eventually white feathers begin to appear on its head and tail in its 2nd and 3rd years. During its 4th and 5th years the "sub-adult" bird develops more and more white on its head. Some breeding adults may have a few dark streaks on their heads and tails when they are 5 years old.
The mottled appearance of the head in your photo is probably due to the effects of light and shadow on the feather edges and also the white down at the base of its contour feathers. The down can be exposed when the wind blows or the bird bends its neck.