advise needed.

So me and my mom have an amazing bond and we are extremely close, I tell her everything. my boyfriend and I had come to  the decision to have sex last month and I immediately told my mom the next day, and she was understanding and we had a really long deep conversation about it, because there's no doubt in my mind about my SO, I love him very much and he means the absolute world to me, and he makes me so happy. I'm 16, and I know some people say you're too young or that I shouldn't be doing that stuff but I don't regret it, nothing felt wrong at all, and it was amazing being able to lose myself in the person i love and put my all into.  But moving on, now me and my dad aren't too close. He's more of the his way or no way and I know I would get punished if he found out about what decision me and my boyfriend had made. And me and my mom have both been hesitant to tell him about what had happened because we're both afraid of what his reaction will be. But we're going to have to eventually. We both feel really guilty for not telling him. So has anyone faced this situation that can give some advise?