She is well aware of the fact that they wish she was normal.
They're supportive of her being a witch, of course, but she knows they wish, well, things had gone the way they planned.
She was top of her class all the way through primary school and they knew she was going to get into a good school, and get all As in her GCSEs and A-levels, and would go to an appropriately intellectual university, and become a lawyer or a doctor.
They were so proud of her, and any time their friends asked, "How's Hermione doing in school?" their faces would light up and they would happily chatter away for hours about how Hermione was doing.
And now they must be vague, and they can't tell their friends that their daughter is top of the class in Potions or Transfiguration or Arithmancy, or that she got eleven OWLs, or that she is considered one of the most promising students to have ever attended Hogwarts.
They can't say that her plans for the future include possibly training to be an Auror, or campaigning for equal rights for non-human magical creatures, things that they only vaguely understand themselves.
It's not what they planned for her. It's not what she thought her life would be like, either.
The difference between them and her is that, if given the choice, she wouldn't change a thing.