How do you know she is Shia? and if she really is, then you will need to speak to your family first, whether they will accept her or not. Because once you and she gets into a pure love relation, it would be very difficult to step back and it would hurt her more than you… since you mentioned, she never spoke to a guy before so dont ruin her experience of love where she will never trust anyone!! so first speak to your family, tell anyone who’s close to you that you are in love and if you see some chance of your family accepting her, then move ahead.
Wish you good luck