How much current YA do you read?
I have to be asking the same question as Springfield now. I actually am a young adult (in high school), and thus far, I'm having to quell doubts as to how relatable this novel is. That said, I don't have lots of information on your book, and every young adult has a very different experience depending on geography, family, etc.
This is what I'm wondering: what is the tone and theme of your novel? What is the time period/setting of this? And how accurate to life are you trying to be?
I've had someone obsessed with me before, and while they didn't end up stalking me, I'm having difficulty equating your version of obsession (which seems to resemble more of a pop culture interpretation) with the more subtle, creepy manifestation of it in real life.
I would echo A.M. Rose on a lot of her points. This doesn't even fully sound as if young adults would enjoy it (it certainly sounds like early young adults, as opposed to older).
That said... none of this may matter, depending on what you're going for. If you're going to comical and light, this might fit very well. If you're going to realistic and serious, this doesn't seem to match.