The year Shannon lost her job, her apartment, and her lover in quick succession, she was thirty-two. The lover was the first to go. She struggled on through the rest of the school year, feeling like she’d been drug across sandpaper, exposed and bleeding. Three Fridays in a row, she plugged in a video over and over, until she heard Bill Nye the Science Guy echoing through her hall at night. She started having adolescent fantasies about Bill. She bit her cuticles. She drank too much coffee during the day and too much red wine at night.
Too much coffee made her vigilant about the cleaning and care of the stacks of cages lining her biology classroom. The rats had never seen so much clean bedding; the snake gorged on newborn mice. She started having one-sided conversations with Jack the Iguana, who eyed her with cold disbelief, and she poisoned the cane palm with fertilizer.
Too much wine made her sleepy and sodden at night, provoked guilty dreams, and caused headachy bursts of weeping in the morning shower.
 

I think you jumped over you hook. You gave me the first line of it, then went into exposition without finishing it. I'm not pulled into the story, I'm pushed in.

You are showing me too much reaction when I don't yet know Shannon well enough to care. All I know is that she seems to be a drunken caffiene-addicted obsessive-compulsive neat freak who kills cane palm with kindness.

A first paragraph is the second-most important paragraph in the whole story (the most important one being the last.) But, it is the first one anybody sees. In that feature, it isn't in second place by more than a hair. The job of the first paragraph is to grab my attention and not let go. Here, you got my attention with the first sentence, then you pull a bait and switch, giving me her struggles. It's too early for that. The first paragraph is doing the job of later paragraphs and not its own job.

I recommend you read through as many of the 13-line postings in this board as you can stand to read. You'll start to get the sense of what works and what doesn't work. It's entirely possible that the rest of the story is fabulous. That doesn't matter if an editor doesn't read that far, so it is a critical skill to be able to craft a beginning. We're here to help.
 

*Ask yourself if Bill is going to play an important part, and if her fantasies about him matter to the story: if yes then leave these lines, if not then cut them. I don't think they tell us anything about her that we don't get from the biology classroom.

**Since we get told about the coffee and wine in the next few sentences I suggest cutting the first reference. Sometimes repetition works, but often it is over used

***I thought the iguana eyeing her was a great line, but it distracted my attention away from the protagonist.

 

If it won't ruin the story, think about changing job/apartment/lover to career/home/husband. At that age, losing a job, apartment, lover, or even all three shouldn't be a big deal to a mentally healthy individual. I'm not saying that you have to change all three. But jobs, apartments, and lovers all have one important thing in common. All of them are stopgaps on the way to a real career/calling/vacation , real home, and permanent spouse-type relationship. You expect to outgrow/discard them eventually anyway.

Then, with whatever modifications you do or don't make to the first line, you need to scrap everything else and design an opening that goes with the entire first line, not just the loss of her lover.

And I reiterate, if she's only lost a lover, her reaction is utterly disproportionate. Even if there are people who react to losing a lover this way (and I know there are), I don't want to read stories about those people.