Your poor niece! And, at the same time, your family has a lot to work through, too. It's hard for people to learn such a thing...not just because of their own thoughts on the subject, necessarily, but also because of the adjustment to the changes they'll see in your niece's life, and seeing their true self after learning this about her. It sounds like either your niece just recently discovered this about herself, or she's been kinda living a double life with it...so it's a bit of a discovery of her true self for the family (if that makes sense), and possibly even about herself.
Me...I have no problem whatsoever with the gay community. I've had gay and lesbian friends, my aunt is gay, my sister was a lesbian when I was younger (but ultimately wound up being "straight", and is now married with kids). In fact, I was very upset that I couldn't vote no on Prop 8 here in CA, due to address issues. I was crying about it, because I really had a problem with the whole issue...and really wanted everyone to continue to have the rights they deserve to have and practice.
I've been an advocate for gay and lesbian rights for some time, and have really strong opinions on the subject (which is why I don't mention how I feel about it very often, as I worry about my reaction to people's replies to my opinions). If we had a second car, and I had a more open schedule, I would have been right there with protesters about Prop 8.
Ultimately, my lifestyle is up to me...as each person's is up to themselves. My beliefs are very liberal in most ways. Everyone's life and how they live it is strictly up to them.
Now, to answer your questions:
1. Should I let her stay with me? I think offering your place is a good idea. And like Peg said, in keeping the communication line open with your mom at the same time. I think your niece would really do well with you, seeing that it's okay to be a lesbian (in your case bi-sexual, but you know what I mean), and adjusting to her own lifestyle now. I don't know where she's at with things...if she's been dating girls in secret and living as a lesbian for a time, or if she's recently discovered this about herself, is new to the whole idea, and isn't sure what to do now. But, either way, I'm sure you have a lot of wisdom you can impart, and would be able to really help her through this transition.
2. What would you do if your child told youtheywhere gay? In all honesty, if my daughter (who is currently 9yo) came to me and let me know she was a lesbian, I would be a bit surprised at first, but would very quickly not have any problem at all with the information (as in, "Wow, Hun...well, that was surprising...but ok. So, tell me what's going on. Do you have a girlfriend? Tell us about her. When can we meet her?" etc). It would be a surprise, but not a problem in the least. I've told my daughter countless times, and will continue to remind her, I love her no matter what. I find nothing wrong with someone being gay, or straight, or bi-sexual. Love is love, and in our family, love is unconditional. Whoever she will be in love with in the future, as long as they aren't damaging to her (as in, a bad person, abusive, on drugs, etc.), they'll be part of the family and welcome to holidays, etc. They'll be accepted with open arms.
3. Is there anything that I could say to my mom to help her out? In my honest opinion, like I said before, do what you can to keep the communication line open. I agree with what Peg said, to let her know that your niece is desiring to move out, and that you have the space available, and the willingness to have her move in with you. Maybe let her know that maybe her and your mom just need some time apart to work on their own emotions/thoughts on the news, and that you'd be more than happy to let them have that space. That's what I would do if I had a niece or nephew come out to their parents (since their parents are very religious, and would probably react the way your mom did).
Also, let your mom know that you're available for her to talk to if she wants to talk about this. Maybe find some sort of information for her about things, maybe a support group for families that have gone through or are going through the same thing. It doesn't have to be a religious type of group. I'm sure there are lots of such support groups out there that are available. Once she's past the initial shock of the news, which seems to be quite large in her case, she might be open to such a thing (and it sounds like it'd be good for her, too).
In any case, I want to send a quick little congratulations to your niece on coming out, and having the confidence to do so with her family. I can only imagine how difficult and scary it must have been. Send her lots of encouragement, remind her that she's a beautiful person no matter how other people might make her feel. I know what it's like to live in a household where you're ridiculed and made to feel less than you are because of a lifestyle choice. I'm not a lesbian or bi-sexual, but I come from a very religious family, and left the church my family attended, and was basically shunned by my mother and one of my sisters, and all of my then-friends. So, I know at least a little of how your niece must feel. Give her a big ol' hug from me, please.
At the end of the day, follow your heart. You know what's best for your niece, for you and your family, and for your mother as well. I hope and pray that things work out wonderfully. Keep us updated, ok?
:hug: