How did Helen come to accept her fate? 

Helen didn't accept her fate overnight. But, it was a gradual understanding of what was going on with her. She clearly mentions 'I do not remember when I first realized that I was different from other people'. She started noticing that her mother and her friends did not use signs to communicate wit each other, like she did but used their mouths. When she tried to move her lips, no sound came out and she gesticulated frantically which eventually resulted into temper tantrums.