Use your pediatrician and nursing staff for things like this. There is always a nurse at the other end of the phone line for questions that are not of an emergency nature, and the pediatrician is also available to make calls after hours and between patients for nervous and even "paranoid" new mothers. (I'm not sure I'd call is paranoia though, because that's an unrealistic fear, and your question sounds more like a normal one.) They'd much rather have you ask a question about something normal than hold back when there might be a concern. And you should be taking her for normal, regular check-ups. Get in the habit of making a list (put a sheet of paper on the refrigerator or next to the changing table, whatever is easiest), and jot down things as you think of them. Then have the list with you for every call and every check up.
Lots of babies get a flat spot on their heads, which sometimes is a matter of concern but usually means you have to keep moving your baby to new positions. Babies are learning to use their neck and shoulder muscles, along with the rest of their bodies. Do you have a book about what to expect in the first year of life? It can be helpful for GENERAL milestones although no one should get freaked out because a baby does one particular thing "later" than normal. Kids do a lot of things in different order (walking, talking) but also skip some stages (crawling, for example). If your pediatrician hasn't recommended a favorite, I suggest you go down to the library and ask the librarian for some recommendations. Read a few, then purchase the one you think is most helpful to keep around for the next year.