I'm Coming Out!...but I need some help

I've decided to sneak out of the closet at 23. Not going for a big production, just to those who are close to me and when the rest find out they find out.So far I've told my 30 yr. old sister. It was her lack of reaction that has me here today. She said "well I kinda knew" and that was it.Now me and her are like PB&J and we talk about everything, Whether it's about a sandwich or our mothers health, we'll go on for hours. We can sing, laugh and cry together. I can't think of one thing we've ever been uncomfortable about saying outloud.Our mom happens to be a lesbian along with 4 or 5 of my cousins, nieces aunts and uncles (God damn genetics) So I truly know she's not offended by my sexuality, We're all very accepting of everyone. I just want to know why she's so uninterested. If she came out to me I would be littering her with questions and comments so I assumed she would too.Has this ever happened to anyone? Is it me just expecting too much? Please give me some sort of explanation so I can continue to open this door, because so far I put my hand on the knob and its not what I was expectingMuch Love ~R