I got some piercings?

I'm 13, fourteen in a couple of months, and I've had one piercing in each ear lobe since I was about 7 or 8. But a few months ago I started getting piercings, and I've now got three in my right ear lobe, and two in my left. They weren't impulsive, and I had been deciding for a long time that I wanted them, and making sure that it was the right decision. However, I went behind my mum's back to do them. She will go crazy if I tell her, and probably make me take them out, and I will also lose her trust. I'm planning on doing my scaffold piercing soon, and also my navel. I'm not becoming a piercing freak, after that I will be done. I've been hiding my ears from my mum, to the point where I've developed a phobia, and pull my hair down every time she walks in the room. A couple of times she's played with my hair, or brushed it off my face, as if she knows, and I quickly pull my hair back down. I remember asking her about a year ago if I could have my navel pierced, and she said something along the lines of 'When your 18, you can do what you want.' But, I haven't waited..and I don't want to take out the earrings because I'm worried I'll get an infection, and I want to keep the piercings anyway. I could probably hide them for another two months or so, by which time I'll be able to take them out freely as they will have all completely healed, but how, or do I tell my mum?