I've been where your at now. A few more years will hurt. My dad starting abusing me around 10 or 11 and i'm 25 now. Like you I didnt say anything and my mom didnt know what was going on either. Keeping a secret like this is a very heavy burden to carry on your own. Talking about it will help. You wont have to spend the next few years wondering and waiting for the next time he abuses you. I know its scary. And it feels like speaking up would make you responsible for getting him in trouble but thats not true. Your father is the one hurting you and your family not you. By talking about it and getting help you are protecting yourself and your brothers and there is absolutely nothing wrong about that. I hope you get help. Dont spend the next few years silently trying to survive his abuse. Your worth more and deserve better than that.