What should I do to make it up to her?

I’m 15 and my mate is 15 too. She has a boyfriend who is 15. I don’t have a boyfriend.she has started to have sex wi him like 7 months ago and she is so happy with him. She sed she wouldn’t have sex for the first time unless it was serious.they have been together nearly a year. But I got really really jealous and he came round to my house to see my bro but my bro wasn’t in but I sed he was. He went up to my bros room. I followed him. I locked the door and kissed him and put my hand down his pants and he was like what the freakin hell are you doing??? He ran out of the room and went to my mates and told her straight away.she sed he did nowt wrong(which he dint) but she came round to my house and told me to stay the hell away from her. I have now found out she is pregnant 6 months!! She dint even tell me. What should I do to make it up to her??