Should I just back off??? Help... :'(

I need some advice... and of course, ranting.

Long story short I have a deep feelings towards a woman who I've started to date, but I'm starting to think maybe I should just back off.
First of all, I think I'm falling for her... I deeply care about her, she has me thinking about her pretty much all day long. And the feelings I have towards her are growing deeper by the minute.

The problem is that she's veeeeeeery Christian (though, Catholic, she has very fundamentalists views... I'm just an atheist), to the point that she feels extremely guilty for been in a same-sex relationship.

It'll be a extremely closeted relationship on her side -which I don't mind at all; for her, ANYTHING-, because when she was around 18 (now she's 22 and I'm 25) she came out to her family -a former partner asked her to and then dumped her after it got messy- and it was a complete disaster. Everything blew up in her face... She pretty much describes it as "hell" and she was sent to a mental institution because of her sexual orientation.

She obviously hasn't forgiven herself for "causing trouble" to her family and she's been four years in an Ex-Gay Christian Foundation desesperatly trying to change her orientation. A part of her wants to believe that is possible to "try" to be straight... that said, as far as she leads me to believe, she's never felt either sexually/physically nor emotionally/romantically attracted to a man.
And I think she kind of resents me because my coming out, though extremely stressfull, hectic and problematic, was overall fine. At the end of the day I was accepted. She wasn't... and undoubtfully, never will be.

Since I "pass" (Hell, her brother and mother know me as her "friend" and apparently they didn't pick up I'm a 'lesbian'), many of our PDA could just be seen as affection of two close friends.
The thing is my feelings towards her will keep growing stronger and stronger and I welcome that... if it wasn't because I feel some reluctance from her to "jump" with me.

IDK... Maybe I'm been too selfish... or too naive.
She keeps telling me that she feels extremely guilty and by extention sad... That god is watching and is unforgiving towards homosexuals (she asked me to hold off sex because it'd be a mortal sin, which I don't mind... I could just cuddle and kiss for a year, for all I care). That she feels she's been a hypocrite to god... That she's afraid to go through what she went before with her family if they find out... And I think she's afraid that I'll get tired of waiting for her and that I'll eventually dump her on the same basis as her former girlfriend... or that I'll cheat on her because she can't be around (but, I would never do that to her.)...

The thing is been with me shouldn't make her feel "guilty" nor "sad". She keeps telling me that "I don't understand", which is true. I don't. I came out at 23... After six years of been an Atheist, so I didn't have to reconcile my orientation with my religion... Also, I came out to a not perfect, but definitely quite understanding family.
And her case reminds me of the "love of my live" (my best friend, who's a gay guy)... He converted to Evangelic Christianity in order to feel accepted... Eventually he confessed me that he even thought about suicide when he was having that conflict. I would never want to put her in such a situation...

Hmm... Honestly writing this has given me some perspective.
But, I want to know from you guys, former Christians... How far should I push?? At the end of the day, who am I to ask her to change for me and "be a lesbian" all over again?
On the other hand... I just can't let her go that easily. I deeply care about her... But I don't feel good being the cause of ther conflict.

Just give me some of your experience...