Coming out to Grandma?

I'm thinking of coming out to my grandmother... It's actually the first time I'll actually be intending to come out to someone. I told my younger sister, "Me too," when she said she gay. Then my older sister out right asked me and I said I just didn't think I liked guys at all. We don't talk about it, though.

I want to tell my grandma though because she's had gay friends back in the 70's and her first husband and her got a divorce because he told her he couldn't stay married to her because he was gay and she doesn't seem bothered by that. She actually acts like it was a awkward yet funny situation. Now, she's made friends with a home health aide who helped take care of her, and is gay. She's very loving, accepting, and understanding for someone in her 70's. One would think she'd be more homophobic as a Christian growing up during the times that she did.

I guess one of the big reasons I want to tell her is because she has a powerful influence over my family. I'm not a Christian, but they are, and my grandma is like the most Christian of them all and they all respect her opinion. If she said she thinks nothing is wrong with gay people and everyone just needs to get over it and show love and respect, I know for a fact that everyone else would rethink their opinion. Plus, I know she'd do this all without outing me to them. (We've shared secrets before. )

So what do you guys think? Should I come out to Grandma? And if I do... How do I approach the topic? I was thinking about asking about her friend to start. Any thoughts?