I think there's two ways of looking at this.
- On the one hand, she's telling everyone about something that you're not really wanting broadcast. And that is making you feel a bit mad at her
- On the other hand, she's obviously very proud of you, is happy that you're getting older and more mature, and can't wait to announce to the world that her 'baby' is turning into a woman
Now, I'm not saying one is right or wrong. But, in times when a lot of mothers and parents are so busy, they don't have time or care about their kids at all, you are very lucky to have one who is obviously very proud of you. My advice would be to just ignore it, and let's face it, she's probably told everyone by now anyway. It's something that will pass, people will forget and you will get on with your life.
Try not being mad at her, I'm sure she's not wanting to upset you