You look great .. I'm really glad that you are looking after your teeth at this early stage
I hardly can see the white spot in the pictures. Even if you have it .. it might be very limited and I would not worry about it.
The best person who can help you with that is your dentist .. as he will examine your teeth in details
There are several reasons for the white spots .. the most common one is something called the DENTAL FLUOROSIS
DENTAL FLUOROSIS, is very common in your age. It is a defect of tooth enamel (the outer layer of your tooth) caused by too much fluoride intake during the early age.
Fluoride can be found in drinking water, toothpaste, fluoride tablets prescribed by your dentist, dental treatment and food.
Fluoride is very useful for your teeth but not too much of it
Be careful .. some of the children at your age swallow some toothpaste during brushing so be careful about that .. and use toothpaste which is suitable for your age and most importantly tell your dentist about it.
Here is a link (video) about Fluoride and why it is useful .. I hope it is helpful
https://storify.com/SusanKing1/the-superhero-of-cavity-fighting
Other causes for white spots are trauma, loss of mineral in the teeth (hypoplasia), braces and poor care of teeth
I'm sure that your parents help you to write this and I'm sure that they will help you to read and understand my answer as well
Best of luck .. again it is minimal in your case so I would not worry about it