Should I Tell My Mother I'm Trans* If I'm Not Sure Where I Identify?

So, tomorrow I'm meeting up with my mother a day out together and a trip to see the family doctor later in the evening. I love my mother to death, and she has always been a very kind and understanding person. I have no reason to believe she will react badly if I tell her that I am genderqueer, and that I feel like it is probably at least partially a cause of my depression and anxiety issues.

The thing is, I don't know exactly what I think. I'm working under the belief that I am an MtF transgendered lesbian, but I'm open to the possibility I may be bi-gendered or even genderfluid. It's all very fresh and new to me, so I'm still in the process of figuring it out.

Part of the reason I want to "come out" to my mother is because I know that I will feel better talking to her about it, and I also know that if she doesn't resist the notion, that she will be an invaluable pillar of support and dispenser of advice. But I also fear that, while she will not be mad, disappointed, or any other such reaction, she may instead simply try and reason that I am simply confused and don't know what I want if I do not manage to put up a confident front on the issue.

I'm worried that, for the same reason I know she would be a powerful ally in my journey, she could just as easily be the most dangerous road block, shaking my confidence in this self discovery with that same power to listen and reason.

I know that I'm not on a time limit here. I don't have to decide by tomorrow or never. But I DO know that if it turns out that she is completely accepting and makes no attempts to damage the foundation I'm building, then I will have subjected myself to the untold amounts of nervous anxiety and self hatred that I always feel when I'm holding onto a large revelation and am too afraid to be open about it. I spent far too long toiling under the weight of anxiety and depression without assistance, only getting worse and worse as time went on, I don't want this to be the same way...

So where do I weigh my priorities? Is it more important to know who I am inside before I look outwards for guidence? Or is it more imperative to just rip the band-aid off and get it over with to shelve these fears and problems before they can snowball?