I often find better material than my original ideas as I'm working and this means throwing a lot of sections out and replacing them. If you do it well, the reader will never be able to see where you've cut ten chapters out and sewn the narrative back together with a whole new plot line. You do whatever you need to do to make it the best book you can. That's the only thing that matters. When you're done the book should be the best you could write at that time.
Writing is one of the more reclusive avocations.
Some writers are more interesting through their work than in person. They may be shy or socially inept or they may struggle in dealing with those in society they find less interesting than them self. You are not but I suspect you know some who are. Actually, most of the writers I know personally are pretty sophisticated people and don't really fit into that stereotype. There are writers who fit your description, I'm sure.