A. First of all, you may want to wait till you finish the whole manuscript before you get a critique. Yes, I understand you want to make sure you’re on the right track, but as you complete the book, you may learn some things about the story and your writing, and go back to revise those first few chapters.
You likely do need a professional opinion. The best option always is to get involved with a reputable writing organization in your area. Some peers will critique your work for you in exchange for you offering your opinion on theirs. But be careful that you do indeed hook up with good people. As I’ve said before, editors and agents don’t steal writers’ ideas. Writers steal writers’ ideas.
Professional editors are an option, and your work should be safe in terms of stealing ideas, but a good editor is not cheap, so you either have to cough up the dough, or risk going with someone who may or may not give you the best feedback possible.