I hate to say it but it could get worse, and probably will. I don't have close siblings so it's difficult for me to say, but I do have close female friends that I can get pretty insanely protective over, so I sympathize with you. You should just hope that she's choosing this guy because he's a good guy and watches out for her. Save the judgements for when you meet him. I certainly won't fault you for splitting his lip if he turns out to be a jerkwad. Sounds like you're coming around alright on your own though. Take care.