What are these white freckles? (photos)

Localized loss of pigment which can be repose,Ted with excimer laser or narrow band uvb. These will require a series of treatments.

Those are basically loss of pigments due to the "death" of the melanocytes due to... sun exposure. I would recommend that you consult with a Dermatologist to go over skin care/protection. 

What you are showing
is fairly common – it is called idiopathic guttate hypomelanosis – and it is
something that happens in many, as we get older. This is a benign condition and
does not need to be treated in any way. If it bothers you, there are some
topicals that can be tried, like Elidel or Protopic, which in some may help. And
there are some who have had success with an excimer laser – many treatments
here may be needed. Consult with a board-certified dermatologist to make the
diagnosis and then work with them to see what your best treatment options are
for you.

You are right, you are pretty young to get IGH, but it depends on your overall amount of sun damage, skin type, and habits such as use of tanning beds, outdoor sports, sunbathing, etc.  Some people do start developing signs of excessive sun damage early.  I would recommend seeing a dermatologist in your area regularly to make sure you stay on top of the condition and discuss proper sun protection and be checked for precancerous lesions.  Good luck!

Thanks for the photo, however for a definitive diagnosis you should consult a dermatologist . IF this is  guttate vitligo than treatments such as phototherapy, and anti inflammatory creams can help. If it is Idopathic hypomelanosis, not much can be done, I think its worth while to get a definitive diagnosis. All the best. Dr Davin LimLaser DermatologistBrisbane, AUSTRALIA