Absolutely nothing wrong with not immediately believing what is presented to you and asking questions. You just have to be able to address facts properly in your questions. Are black holes guaranteed to exist? No. Are they currently the most likely candidate for what occupies high gravity wells strong enough to bend light? Yes. How can we test to see if something actually is a black hole? Well one way is to look at it. Funny enough, just recently humanity managed to pull that off. Look at the photo, and question what things do you think could’ve made that photo that don’t break the facts of how it was obtained. Fact, it was done by a large number of people using telescopes around the world, and then it was processed by even more people. You’re not going to create a convincing argument that every human on earth involved is hiding a cover up. So you need to take it as a real photo of something very far away. Do you believe certain stars might burn fuel in a way that absorbs light and emits a higher form of radiation that could decay to the white ring we see in the photo? Do you believe something else? You have to start by critically thinking about the evidence in front of you, and if you can come up with a testable hypothesis about what you see then you SHOULD bring it to other people, you SHOULD test it yourself. And once youve tested it a whole bunch and you have an answer, then you should start asking questions about why you got the conclusion you did. There will always be more questions because that’s how the science rabbit hole works. But at the end of the day, don’t take a given answer at face value if it feels wrong. Come up with a way to test, poke, and prod what is generally considered common knowledge. That’s how we as a species grows.

Edit for reference the radiation decaying is me totally making something random up. I am not suggesting that by any means