My neighbor asked to move in with us...

Backstory: My former neighbor, who I am friends with and still hang out with sometimes, seems to be happily married but struggles with a few issues like drinking and stress caused by her step-children. She is a nice person, but hard to be around for long periods of time and can be hard on the kids. My husband and I moved into a house a couple of months ago, and my neighbor was disappointed and basically not happy for us since we decided to move away (but only about 10 miles). Our new house needed totally new plumbing (we did the work ourselves and finished last week) before we could actually fully enjoy it. While we worked on the house, we stayed in our "mother-in-law house" which is basically just a tiny building with a tiny bathroom in it. Now it is full of stuff waiting to be unpacked or find a final place. Our house is a disaster.
Situation: last night at 9:45pm my former neighbor sent a text asking if she could move into our MIL house for a few months. No explanation.  A few minutes later (according to my phone) she sent a message saying "please" and then, when I hadn't responded she sent a message that said "Sarah is eerily silent." I was asleep, so I didn't see it until the next morning. I sent back a message explaining, kindly, that we really didn't have the space available right now, and maybe if we hadn't just moved and had things unpacked we could accommodate her. She said "thanks for considering it" and left it at that.
My question is: now what? I feel offended that she even asked, much less through a text late at night with no explanation. I feel more offended that she seemed impatient with my lack of a response. I want to know what is going on, but she did not feel like sharing, so should I even ask? I care about her well-being, but not enough to add even more stress and chaos to my already overwhelming life - is that selfish? I get easily irritated by things, and this situation really put me off and left me feeling uncomfortable, so now I don't even know how to talk to her! What would you do?