Telling my sister

I am 4 Weeks pregnant. I lost my first ever pregnancy early Sept at 6 weeks. I didn't tell anyone because as soon as I found out I started miscarriage. My dh and decided to keep doing what we've been doing and if it is meant to be it will. My sister on the other hand has been trying like crazy for the 2 years she's been married. I want to have her support though this she is a nurse and really good at this stuff. My hubby tho thinks it may be asking too much. But I feel that I am older than her and my time is ticking this will probably be my first and only child. She already has one birth child and two step children. Am I being too insensitive? I am sure she will be a little hurt but she will also be happy. How can I tell her without hurting her? I want to be happy too. As soon as I tell my mother the entire east coast will know before sunset.