It's kind of a no brainer that they don't know each other well enough yet for marriage, but that's what this all is anyway. Dating with the intention of marrying has the end goal clearly stated, but you still have to do the dating bit. Get to know each other, make a final decision. It'd definitely be nice to see them reach the stage of "this is not a perfect human being but I still love them anyway" before then for sure though. Her dad's made a great point and all.