I'm reading a book , and I don't understand this small phrase. Could you please tell me what it means, thanks.

~Or they'll be so horrified by my mother's newly-found 'lifestyle' that they'll slowly start ignoring me. In tenth grade—at least in Vienna, Virginia—this is the kiss of death. Even worse than not being one of the cool crowd. Which is the type of person I currently am. Not quite cool, that is.

To be more specific, I don't get the line starting with "In tenth-grade-.... ending with kiss of death.

She's saying that her mother's lifestyle will be ridiculed by her classmates and that she'll be shunned and ostracized.

Oh, thank you very much Ms. Sue:-)

You're very welcome, Sara. :-)

In the given passage, the line starting with "In tenth grade—at least in Vienna, Virginia—this is the kiss of death" is referring to the situation where the speaker's peers or classmates might start ignoring them due to their mother's newly-found lifestyle.

The phrase "in tenth grade" indicates that the speaker is currently in the tenth grade at a school, specifically in Vienna, Virginia. Then, the phrase "this is the kiss of death" is an idiom meaning it is a disastrous or extremely unfavorable situation. So, in this context, it means that being ignored by their classmates in the tenth grade because of their mother's lifestyle is considered a very negative thing, even worse than not fitting in with the popular or cool crowd.

To understand the significance of this statement, it might help to know more about the speaker's circumstances, their mother's lifestyle, and the social dynamics of their school or community. The phrase suggests that being ignored in the tenth grade is highly undesirable and can have detrimental effects on the speaker's social standing.