How do I convince my mom to accept my religious beliefs?

[TheKtLLERAnna]

Yesterday, my mom found out that I was a bisexual agnostic. Needless to say, it was a "splash of cold water to the face for her." <her words. And while it's refreshing for her to see who I really am, we're having some serious issues, because we don't understand each other. She can't see how I can accept that nobody can know what happens after life, and I can't understand how she can be so closed-minded to think that just one way is "the truth." Anyway, it leads to a lot of mutual pity, and pity, and argument, and anger and such, and I don't know what to do about it. The sexuality thing is a whole other argument. What am I supposed to do about it? I want her to accept and respect my opinion...how do I do that? What can I possibly say? Please no insulting answers. [Keep in mind the god of the Bible =/= the FSM to her. Lol.]
she wants me to go on a "spiritual journey," convinced that my agnosticism is a "cop-out" and if I'd go on said journey I'd find out that Christianity is "the truth." I think this is bullsh*t, obviously, coming from the perspective that truth is relative. suggestions?