When you are ready to tell people, just tell your friends matter-of-factly, and don't be hurt if/when they don't get all excited for you.
Many years ago my friend and I were trying to get pregnant at the same time. We had both had miscarriages previously. We both thought we might have pregnancy symptoms, so we decided upon this dumb idea that she would come over to my house and we would take our pregnancy tests together, and then of course we would be really excited together when we found out we were both pregnant. Cute, huh?
Not cute. We did our dip sticks, left them in the bathroom and then waited for a few minutes. At the appointed time, my friend preceded me back into the bathroom, looked at our tests, stomped back out and petulantly and ungracefully barked, "YOU'RE PREGNANT, I'M NOT." Well, talk about taking away from MY moment. I realized the whole thing had been a dumb idea, but she should have had the good grace and manners to try to be a little bit happy for me.
Anyway, she got pregnant a few months later, and years later we both have our girls, so life's fine for all. But life is what it is, and hopefully your friends are classy enough to not make you feel bad about your good fortune. You have a right to get pregnant and feel happy about it, and obviously, you have to break the news to them somehow. Just tell them, and then don't expect much.