Like many people you over-simplify. First the term is hyperopia which people call 'farsighted' It really means the eye is too short or the cornea too flat. Depending on the amount people, especially children may have no symptoms or may not be able to read at any distance without glasses. You also say she had +3.5 "cylincer power" that means astigmatism and is different than farsighted, or nearsighted (myopia). It does appear your child needs glasses. You can always get a second opinion if you are not comfortable. If you have other children check them as this often runs in families.