I can say you've overcome the first hurdle any author faces - you've kept me (your reader) interested.  This is a good start, and I'm looking forward to what comes next.

Seeing as your note at the end is asking for ideas and suggestions, I'm going to offer some criticism on the content above.  Please take it with a grain of salt - every author writes in their own way, and different approaches appeal to different audiences, or set different tones for their story, or suggest different levels of investment.

This first chapter leaves a lot of questions in the air.  This is a good thing; you want your audience asking questions.  It keeps them engaged, and anticipating what comes next.  There are two important qualifiers for this, however: 1) You want to prompt the audience to ask the right questions, and 2) you should have at least a basic grasp on answers to the important questions.  Questions like, "How did Jane and her friends end up in that horrible situation" are exactly the kind of question you want to leave your audience with to keep them interested, and something like, "They were pets who were stolen but managed to escape and were just trying to get home," is an answer you should have already answered for yourself when writing this chapter.  I write this so I can frame the big questions I have at the end of this first chapter.

1.  Why is Emily not surprised that Jane is tiny?  This is a very simple question, but the answer, and when you reveal it, have complex connotations, and could very well be a significant element of the story.  If tiny people are the norm, then the lack of surprise makes sense, and the answer to WHY they're the norm becomes important.  Are they a different species?  Are they victims of a virus/government testing/technology used illegally?  Or more intriguing, are they not common knowledge, but Emily is unsurprised because she is one of the few people who has met a tiny before?  For example (since I'm in the dark as to the true nature of tinies), Jane could be a borrower, in the theme of the classic folk tales.  Most people don't believe they're real, but Emily met one when she was a child.  Maybe something happened to this friend that inspired her to do good works, like working in a homeless shelter.  Maybe Emily did something to hurt this friend, and is now trying to make the best use of the rest of her life to atone.  The more clandestine answers are all things that could and should be revealed later, but if tinies are commonplace, that is something you should reveal to your readers early, so they are not surprised or disappointed later.

I know there's a ton of fabrication, conjecture, and smoke & mirrors here, but the point I am trying to make is that, when a character acts in a distinguishing manner (when they do something out of the norm), it needs to be informed by their past.  One of the most important things you can do is to be true to your characters - and whatever half-thought-up or 20 page detailed backstory you have for them - and to understand that if that character acts in a way that would be unique to them, or would break from common expectations, the reader will assume that the character is acting differently because there's something different about them.  To be clear, I'm not trying to make you second guess every action a character takes.  If Emily got a coffee with extra cream and two sugars, all that would tell us is that she doesn't like bitter tastes, she isn't averse to caffeine, and that she probably has a sweet tooth, but it's not story relevant.  The reason this reaction is important, is that the answer informs your setting, it potentially informs Emily's history, and it is an obvious departure from the norm because any of your readers would be surprised to find a tiny girl in the real world.  NOT being surprised highlights a difference from the readers, 'normal.'

2. Is Jane wearing any clothes?  No, this is not the horny talking - ok, not entirely - but the answer to this question actually informs many of the worldbuilding details that would similarly be informed by the answer to my first question.  If Jane is naked, that implies that tinies are feral / lower class / pets, or that something truly awful happened to her between leaving safety and being rescued, and I don't just mean the cat attack, unless it clawed her clothes off without hitting skin.  If Jane is wearing clothes, the kind of clothes inform further details of the world.  If the clothing is cobbled together, then Jane is either poor, or forced to make due in an unusual situation, or is better cared for than the average tiny.  If she is wearing scaled down clothing with factory or loom quality, then this implies further things about her lot in life, the status of tinies, suggests she was shrunk by technology, etc.  I suppose the point I'm trying to make here is that details matter.  You don't have to provide a ton of detail, but consider adding a few more considered details that can combine to more naturally convey information about your world to your audience.  

I'll list a couple more questions here without the long-fingered explanations, just to help you get thinking in case you haven't already answered these questions for yourself.

3. How did Suki end up as Shana's minion?  Usually socio-economic factors have a heavy weight in social interactions, so this development is definitely tied to something in Suki's character.  Did Shana's physical strength initially intimidate Suki, and learning more about Shana later eventually brought Suki around?  Is Suki a sub?  Does she have a foot or B.O. fetish?

4. How old are these college-age characters?  Dorms usually suggest underclassmen in an undergrad program.  Are Suki and Shana Sophmores (second year students)?  Is Maya a Freshman who plays with dolls?  Is Shana's whole family visiting?

I think that's plenty to be getting on with for now.  I want to again say to take the above with the understanding that I am not a professional author.  I'm just trying to help you think about your setting and characters when you write, and how to incorporate those elements into the story.  What you have here is a great start, but if your goal is improvement, then I would be honored to offer what context I can to help you improve.

Please retain the courage and confidence you had when you posted this first chapter to continue writing, and most especially, thank you for sharing your story with us!  I look forward to reading what comes next!