How do people know they are born in the wrong gender

In what way are you uncomfortable in your own skin?

So far, you sound like a cis woman, and it doesn't seem like you have anything to worry about. Thinking life would be easier as a man or being curious about what it would be like to be a guy having straight sex is not abnormal. Regardless, don't freak out. It doesn't seem like you're trans but if you are, it'll be fine.

To answer more generally, I can tell you a bit about how I knew I was trans. The main way I figured it out was when I started realizing I had top dysphoria. I realized that a lot of days I would be more comfortable with a flat chest and started trying to bind with materials I had in my room. When I found out this was something a lot of trans people did, I was immediately excited at the idea of not being a girl. This was because I had been uncomfortable being female but hadn't realized it, so finding out that there were other options was a relief. I decided for sure that I was trans when I found out how much more comfortable I was binding, being referred to by a non-feminine name, and not using she/her pronouns. I wasn't sure for a long time of what my gender was exactly, but that's how I knew I wasn't cis. It had nothing to do with the clothes I wore or the gender roles I fit. It was just that I knew I wanted to be seen as a boy, and I knew my body wasn't quite right.

 

You've probably read this a thousand times before, but nobody can really tell you whether you are trans or not. It's certainly a process, some people have known all their lives, for others their was a time when it just clicked and everything fit.
How long have you thought about your gender, if you thought about it at all? If you generally ok with being perceived as a woman and being addressed with female pronouns, I think it's safe to say you're not trans, although I don't want to make any assumptions about you. A lot of cis women have probably wondered what it would be like to be a cis men, whether they would like to stand up while peeing during outdoor activities or because of any sexism or stereotypes they face.
There's no need to freak out. Try to get more information about transitioning and if it could be an option for you. You already said that one reason for feeling uncomfortable are because of your sexuality (not being out etc) and not necessarily because of your gender. You could also experiment with different gender expressions to figure things out by wearing more masculine clothes, maybe get a binder or a sports bra to hide your chest and look out for any emotional changes.

 

Why did you write that you are ok being a woman? What makes you feel ok about it? Do you feel a certain sense of comfort and familiarity in being a woman? When you wish to be a guy you create a clear distinction between being a woman and a man and put yourself on one side of the binary. From the statement it reads as if you know that you are a woman but wish that you were a man. Ask yourself, if you woke up tomorrow and looked like a man, would you be on the other side of the binary or would you still be a woman inside? How would you feel if people started responding to you like a man while you still felt like a woman deep inside and you didn't have the tools needed to navigate the situation. Yes, your body is that of a man and you have muscles but you are still you. Your body doesn't feel like your own but just a mask that you are wearing and you still feel the same barriers that you feel now that seperate you from men, you are on the other side of the binary. Well, that's how it feels to me to be trans, I can wish to be a man, my brothers lives might seem so much easier to me than the life of a woman, however, I will always be a woman deep inside and it doesn't matter in the slightest that my body is that of a man...