Hey there, am an Australian from a Muslim family. I too have the same, yet opposite, relationship dynamic as you - though our families are both aware now.
Formally, it is considered forbidden for Muslim women to marry outside the faith; her family won't take it lightly. Perhaps in ways you haven't considered.
Talk to your girlfriend. Ask her what she is worried about, and she will tell you. That is the best thing you can do.
Perhaps Lemmy should offer an option to delete the OP and retain comments?
I would also like to see some of the comments even after the original post is deleted if the post author is ok with leaving them up.