i was 13 (2 months from being 14) when i started going out with my now dh.
He was 19. I lied to him about my age, and then kept it from my mum and dad, because i knew he would find out how young i was. I lied, and lied and lied ..... forged notes to get out of school early, lied to friends, got friends to lie for me you name it i would have done it.
I had previously never lied to my parents, and do feel bad now , but at the time it just seemed like it was what i had to do.
eventually they found out, and went mad, tried to stop me seeing him but by then we had been together nearly a year.
I was very grown up for my age, had always mixed with older people and was physically grown up too, had started my periods at 10, and was the same height etc as i am now.
i ended up getting pg and having my ds just as i turned 15. From the outside i'm sure he got the blame, but i can honestly say i instigated all of it - everything, from getting together with him, to finally sleeping with him.
My honest advice would be to talk to her - stay calm, even if you are panicking. Ultimately, she will do what she wants. I couldn't have talked to my parents AT All, and still can't really now i'm 30. I think that is what i want to be different with my dc, and certainly have always been very open with my ds (who is now older than i was when i had him!)
Perhaps invite him over, set some reasonable ground rules i.e when they can see each other, homework being a priority, etc if he is serious he will do it, if not he wil run for the hills!
Best of Luck x