Discussing Plot

I was describing my new story to a good friend last night. I am not good at condensing things down to a short statement, and this friend wanted to know the backstory and other things that if she were reading would not be apparent until later in the story. Now I have two questions about having this kind of conversation.

1. Does discussing plot with someone who will have questions/comments (but who hasn’t read the story) influence my future decisions too much?
2. Am I ruining a potential reader?

Or is it all part of keeping me motivated and focused? People are bound to ask about it, especially when writing this blog. I’m beginning to think I should come up with my “elevator pitch” or short statement to tell people and be done with it.