Thank you for reaching out. I believe this is a really essential and critical question.
"Be yourself". How often are we told this by our parents, peers, colleagues, and in general most of the world? It's easy to tell someone to be themselves, because the rest is up to them, not us. You can be told to be your true self, but chances are, this is a difficult process because the world may not be able to accept your true self. In general, when told to "be yourself", many people often mean it's acceptable to be yourself as long as it fits within the construct of societal values and norms. It's a blanket term that is used as a form of politeness rather than pushing someone to accept who they truly are.
You mentioned that it is easier to pretend that you fit into society's binary concept of gender. It may be easier to fit into this binary form of gender that is constructed as the 'norm', but it comes at the cost of many feeling like they have to hide who they truly are.
Let me begin with a saying by Abhijit Naskar- "computers are binary, not people." There is truth in this, because the choice between one of two seems ridiculous in a world filled with billions of people. No two people are exactly the same, so asking to identify as "either or" is a way for society to simplify and mainstream identifying and recognizing a person. It's easier for companies, governments, and schools to have a box to check off so they can organize their data more efficiently. However, organizing 'people' is a little synonymous to comparing them to the binary system of computers. Despite this, it is a practice that has become commonplace today.
How you identify yourself is completely up to you, not those around you. Even if you don't fit into the boxes written on official forms, it is not your job to change yourself to do so. However you feel most comfortable being you is the way you should present yourself to the world. Protecting the world's feelings and reactions is not your job, and while it may be 'easier' to just blend in or fit in, remember that those who tried to fit into the world were never the ones that brought change to it. The difficulty you feel finding your place in the world is an obstacle, but it is not one that is inherently 'bad'. Going through it will allow you to grow and at times, discover more about yourself than simply hiding it.
To the world that has a hard time accepting you, think about where it started and where we are now. There was a point in time where people of certain races weren't even seen as people; a time where 'white' was the norm. Furthermore, the concept of binary gender is one that is man-made. The term 'he' and 'she' is used in language because it is an easier way for people to identify someone, but it is not set in stone. Again, there are billions of people in the world, all with different names and identities. Choosing your own identity is not something that is new; it may just seem new and foreign, because the type of identity you are choosing may not be 'easy' to accept in certain languages, but that is by no means a reason to stifle yourself to a point where you feel like you're always hiding.
In identifying yourself, remember that there may be times where you receive push-back from those around you, but don't let this stop you from continuing to be yourself. What you do need is to learn how to cope with it because it is true that you can't change the world's thinking, but what you can do is learn to deal with how you react to it. Instead of letting it bring you down and fall into depression, find healthy ways to cope with others reacting in a negative way. These could include speaking to a therapist or finding healthy outlets to vent such as journal writing. Finally, express how important your identity is to the ones closest to you. If your family and friends surround you with support, then the rest of the world is easier to deal with. Create a support system that you can fall back on. The answer does not have to be hiding who you truly are.
To those that have a difficult time accepting the concept of non-binary genders, think about how billions of people have different names. Do you call them by a name that is easier to say? No, you don't. You call them by their own name, because doing anything else would be extremely derogatory and rude. Similarly, how someone identifies themselves is what should be used in conversation with them or about them. Failure to do so would again be doing what's easier for you, not what is right for them. Mistakes are okay, but learn to consciously work on correcting yourself to make sure that you are appropriately identifying someone how they chose to identify, not what you choose to identify them as.
I hope this is helpful and I want you to be confident and start to believe in yourself and be compassionate with yourself first then others. Taking therapy would be very helpful in that a therapist will work on your self critic and would help you optimize your self worth in your own eyes. I wish you the best!