I’m a horrible person

When I was 13 I sucked my 9-yr. old neighbor's cock AND licked his asshole. No regrets whatsoever. I still get hard thinking about it.

Look you made a mistake and based on your age I can understand, especially the way the world is today. I would suggest you talk to your step brother and apologize, let him know it won't happen again. Hopefully it won't impact him later in life but just rebuild the trust he had in you and try to avoid watching things online that might push you to try this again. When you are a man you can decide what you want to do in life but with other adults. Just stop freaking out and make this a learning experience.

If you are close to your parents and you feel you can speak to them, go ahead, they may initially be upset but if they love you, they will understand and try to help you get passed this, good luck