K.F. - I thought it was stngrae that given the names and the balcony scene, there wasn't a reference to the fact this is a retelling of Romeo & Juliet. The reason I'd stop reading isn't for the premise itself, which I think can be a fine romantic YA drama. Rather, the Romeo & Juliet angle seems out of place. I wasn't sure what the real story was. Remember that Romeo & Juliet is not a romance; it's a tragedy. So, I'm not sure where that story fits into this story, given the situation you've set up. Oh, and I think it's perfectly fine to swear in queries as long as it makes sense and isn't gratuitous.
"Relationships don't stand a chance with Jess after the loss of her fetahr, for which she feels partly responsible, and the gradual realization that the only man she ever loved is dead."If I were an agent, this is where I would stop reading. The sentence is confusingly worded, and makes me wonder if your story will be, as well. Aside from that, if she's only 17, it's not exactly a desperate situation that the only man "she ever loved" is dead. She'll meet someone else. Unless you mean her fetahr, which, from the way the sentence is phrased, you might. I read your first 250 words anyway, and wouldn't personally be interested because it is so apparent that your manuscript is a "modern" Romeo and Juliet, which has been overdone to the max already, IMHO.