I don't know if it's an all or nothing thing. It's not binary, for lack of a better way to describe it. I was obsessed with growing up as a woman when I was younger. Then puberty hit, and I didn't think about it again until I had some natural body changes in my 40's, which (aside from the pain of it) I really enjoyed. Started hrt recently, so as of now, the downside has completely gone away. But it's not easy, and coming to the reality about how you feel about it, and what it means to you and the people around you is really the most difficult part. I'm still struggling with it, but that's okay. I'll get there. Sometimes, you just need to sit down and think about things, and be honest with yourself. I do think cis people ask themselves the question, but I think when they do it, it's a very quick answer. If you're sitting there, struggling with it, you might not be a cis person. Then again, you might be.
Try this exercise. Imagine yourself waking up, and going through your day as the gender you're thinking about. Try to get every detail in. Putting on your underwear, going to work, doing your job, taking the bus, whatever. Imagine the little things. Does anything change? Is there anything that bothers or scares you about this imagined scenario when you painstakingly walk through that door in your head? Do you feel better, worse, or about the same when you think of these things? Do you have a strong emotional reaction to it? That should give you a springboard. A starting point to reasonably and rationally have this discussion with yourself. Pay close attention to any strong emotions you counter when you do this, and ask yourself why you feel that way. I don't know is a totally okay answer. You can get to the bottom of it.
Hope that helps.
