<human>: EDIT: While my girlfriend's mother is catholic, my girlfriend herself is atheist.

My girlfriend and I have been together for roughly four months and we are both college freshmen. Long story short, it turns out her mom is extremely catholic, to the extent that she cannot conceive of anybody not being catholic or her daughter even knowing anybody who is not catholic. I am an atheist, but I'm very relaxed about it (I'm not a dick, I promise =]). Unfortunately, taking the "let's respect each others beliefs" approach is not viable, apparently she just won't accept it. To top it off, her mom is also literally crazy and has spent time in a mental institution. I am fine with her mom not liking me (well, I'm not happy about it, but I can accept it), but I'm afraid it might cause real problems. Her mom is paying for her college and her study abroad program this summer. Her mom cutting these things off seems to be a very real outcome in the worst case scenario. Also, she doesn't know I exist yet.

Anyway, reddit. It seems I only have three options, and I'm not sure what to do. 

We can continue to pretend I don't exist, but I don't think this is going to last forever and isn't necessarily healthy.

I can lie to her, although I'd really rather not lie to my girlfriend's mother. Also, I don't think I could pull it off even if I wanted to.

Finally, I can be upfront and meet her, telling her that I am dating her daughter and I am an atheist. This could end with very bad results.

So, reddit, any thoughts? I could really use your help in this, I'm at a loss here.

Summarize the given text in a few sentences.
<bot>: My girlfriend of four months has a mom who is literally crazy and cannot accept atheism. I am an atheist, and when she finds out about me this could have bad results. What should I do?