Most importantly, this wasn't your fault. You didn't know his actual age until after right? How could you be the one to blame then? It's on him for lying. As for continuing after because you were worried he'd already told his friends? And though I can't say what you were thinking, you likely felt like you were backed into a corner and you didn't know what else to do. It's definitely not something easy to deal with so I'm sorry you were stuck in that situation. The best advice I can offer is to distance yourself from him. Maybe even ask your parents or someone you trust since it really wasn't your fault. He lied, and you felt like you didn't know what else you could do.