When you want to make a career in politics, you must take positions on issues. No matter if you want to make it in a democratic or an autocratic system, you will require people to support you. And other people will only support you when they know that you share their political positions. When you are silent about your positions, then nobody will try to stop you, but nobody will try to support you either. If you want to gain political support, you need to convince people that you can further their agenda. And you can't do that by keeping your agenda a secret.
Yes, there will be people who oppose you, because your ideas go against their interests and/or beliefs. But you can't make it in politics without making enemies. All that matters is that your friends outnumber your enemies (not necessarily in number but rather in power). A famous quote often misattributed to Winston Churchil says:
You have enemies? Good. That means you've stood up for something, sometime in your life.
So publish your opinions, loud and clearly, and seek contact with those who share them.
There is, however, one thing I am skeptical about. You are just 18. I know, you think you are an adult now. But politically-speaking you are still young. Very young. Few people make it far in politics before they are at least twice as old as you are. It might be a bit early for you to write about political principles and ethics. If you want it to be taken seriously, you would first have to prove that you actually know what you are talking about. Either by having some academic qualification in political science or by already having a successful career in politics or journalism. At the current point of your life you might want to stick to social media or blogging to publish your political ideas.
Also be careful about another thing: Make sure that the opinions you want to express aren't actually illegal to publish in the country where you are living. When you are living under a regime which practices political censorship, be careful about what you write. You can't influence politics from prison (or when you are dead). Stay within the legal boundaries of the system you want to change.