Ultimately, only time and both you and your GF have the answer.
A couple of big factors however are:
- how dedicated she is to her beliefs, and will she ever expect you to attend church with her for an example? Also, is she out to change your beliefs or behavior? (not blaspheming God/Jesus Christ for example)
- how does her family feel? If they are devout they will likely not be supportive of your relationship, and that will definitely be problematic
I think as long as you both undrstand that you are entitled to maintain your separate beliefs you’ll be OK. There will be times you will have to agree to disagree. As long as you both remain open-minded your relationship should be fine.
I think it’s beautiful, really. Much luck to you!