I'm really close to my mom, she's one of the only people I talked to about questioning being gay, and the only person I talked to who wasn't a counselor or LGBT activist. That was about two months ago, which was several months after I started questioning. Now that I've had more time to think though, I think I may actually be asexual rather than gay. I'm afraid to talk to her about it though for several reasons; I'm afraid of what she'll think if I tell her after I already said I thought I was gay, like I keep switching and I'm just confused. I'm afraid I might upset her. She's a wonderful and supporting mother, but when I told her I thought I was gay, she sort broke down a bit because she was worried about me and how my life might be harder. I feel like she might react in a similar way. I'm also a little afraid of the attention she might give me. I'm afraid she might want to talk about it a lot, and try to "help" me. That's not really something I want or feel like I need right now. Another thing is I'm still so unsure, I don't want to say something to her and then decide I'm not asexual next week. I would like to tell her, but I'm just so nervous.
Well, lets look at this in a different way. Discovering your sexuality is a definite process for most people, and that will definitely need to be brought up. If your mother wants to talk about and that makes you uncomfortable, just tell her that because she needs to respect that.
The problem with that is partly because of how it went before. When I told her I thought I was gay, she brought it up one morning and in my head I was thinking I really don't need to talk about it anymore, but then I saw the tears. She needed to talk about it, not me.
I think that very, very, very few people are genuinely asexual. My understanding of the (little I've read in the research on this topic) is that most who think they are, actually have something going on that's affecting their sexual drive... and once the underlying issues -- usually shame-based -- are addressed, the so-called "asexuality" goes away and the normal, healthy sex drive returns. It's easy to get oneself into a dangerous headspace by self-labeling with terms like "asexual" because it can prevent one from actually working on the core issues behind it. So as far as your mother goes... if I were in your position, I'd put time into exploring where I really was, with a therapist or other helping professional, before adopting that label and perhaps creating unnecessary strife with your mom.