What did i just do??!

I gave my friend's brother a blow job. Him and I were waiting TV and then he had his hand in his pants and I said, "are you trying to keep your hands warm?" Lol he was like I'm trying to keep this warm and pulled out his dick. Then he was like wanna suck it? I said, "ummm... I shouldn't. Your sister is my friend and shed kill me if she found out." He said "well she won't find out. I can keep this between you and I." I wasn't sure what to do then he's standing right in front of me with his dick in my face. Well I did it. And I feel bad. What if she finds out?? I broke girl code.