Did you like my story opening? Does it make you want to read more?:
Actually yes it does. To be honest, it's an interesting way to set up what I assume you have planned. A good way of introducing the main character, the conflict, starting questions, tying off what we need to know. Its all beautiful. Tied up in a neat little package.
Anything I could improve on (does anything seem off, boring, grammar mistakes, etc)?:
Like Ranger's already said. Paragraphs maybe a bit of punctuation.
The only thing that was really glaring at me at any point was the use of breathe instead of breath. Which is really easy to misspell and look over. But otherwise everything else looks mighty fine.
Do you think it's a good or bad idea to start the story off from the not-quite-main-character's prospective to create a bit of mystery?:
Honestly, it can go either way. It's not necessarily a good or a bad thing in itself... Its uh.. More of a grey area than anything. If you can make it work do it. If it makes sense do it.
The only really good advice I can give you is write what you want to read. Do what you think is fun. Experiment.
If done good starting stories like this make everything more questionable. In a good way not in a bad one. It starts the questions in their head that are bound to circulate into theories you hadnt even thought of.
If done bad then it can leave the readers confused and lost within the story before you've even started.
I honestly believe you've done the former rather than the latter. So great job and keep writing :3