QUESTION: Is it okay to leave the reader a little confused so that later on, when I reveal the secret to them, it’s surprising? My main character withholds secrets from others and from the reader.
It depends on what you mean by confuse. If you are leaving out information so that what is happening makes very little sense or the main character is behaving in a bizarre manner with no real clue why she is, that’s a very bad thing. If you give the reader more than a few “what the heck is happening, and why is she behaving like this?” moments, then the reader stops reading.
If you mean not giving the reader all the information, that can work, but it is a tricky dance between giving the reader enough information and lying to the reader by withholding too much.
With a major viewpoint character it works to leave out information if that character isn’t thinking about something. Readers don’t feel cheated if there’s really no reason for that character to be thinking about this subject, but, if this subject is up front and center in her thoughts, then the reader would feel cheated if important information is left out.
As a very broad example, imagine the heroine thinking during her first meeting with a guy who is attracted to her, but later, it is revealed she’s lesbian. That’s leading the reader astray in a dishonest way. If, however, she was married to a jerk who beat her, this information doesn’t have to be revealed until later unless there is a reason for her to fear the guy who is attracted to her.
If it feels dishonest not to tell the reader something, then the surprise isn’t worth it because you may have lost the reader before the surprise is revealed, or the reader feels betrayed and lied to.
If you are confused about what to do, do it the way you feel works then trust your beta readers or critique partners to tell you if this works or not.