This was kicked from the relationships sub and suggested that I post here... I (42M) have a daughter (18F) who wants to travel to meet up with a guy (47M) who she met online

I think the mods over there are a little overzealous. I admit I am a little salty because of that. I apologize if this material is inappropriate for this sub. But I really want some perspective on my problem. Thank you!Here is the original post before it was removed: http://ift.tt/2gBGxbq guys. I need help. As the title states, my daughter wants to take a two-week trip alone to see a much older man in December.She dropped this on me a few days ago and I was floored. Of course, I said no. It came up again last night and she is determined to see this man. My mortified face when she referred to him as her boyfriend.A little background: My daughter was pretty much a straight-A student. Last year she attended the governor's school (a selective academic summer program, which is a pretty big deal in our state). She was able to land a low-level "grown-up" job downtown working at a marketing firm. In so many ways she is more brilliant than I could ever be.On the flip side though, over the past few years, she has been suffering from major depression. I guess due to the stress she puts on herself. She was barely able to find the will to make it through the last few months before graduation.We currently have her in counseling and she is on medication. We convinced her to take a year off before going to college so that she could focus on her job and her therapy. We want her to get into a good place before she goes off to school.I feel that she is still very naive. She doesn't know much about dating or relationships. She has always been focused on school. She has never had a serious boyfriend.Lately, I knew that she had been staying up late chatting with people online. Her siblings have come to me concerned with the sites that she would choose to visit. BDSM type sites. In the back of my mind, I knew that something was up, but I figured it was okay to let her explore. It was a difficult conversation but I told her that I was concerned and that I loved her and to be careful.I had no idea until the other day that she was talking seriously with an older man. This guy is 5 years older than I am! Almost a 30 year gap in age. I have always tried to be pretty lenient/liberal and understanding when it comes to my kids. (I grew up in a very strict Christain household and I strive to give them the exact opposite of that.) But this age gap is a line that I can not possibly see past.I figure that her behavior may be a reaction to us not letting her go to college right away. She wants so badly to be independent. This could be a way of her rebelling but I worry. I feel like this is a very dangerous situation and I just want her to be safe.There are so many red flags. I know nothing about this man other than that they probably met on a site specifically geared towards men meeting much younger (underage?) women. Who knows if he even gave her his real name?I feel like he has to be manipulating her and taking advantage of her inexperience and sadness. Why a two-week trip to see him? At the very least if this was a real attempt at dating her, why can't he come here? Even that makes my stomach turn, but it would be better than the alternative.She insists that he is a good guy and she assures me that they respect each other. But everything about this seems to scream "predator"!Since she is now 18 there is nothing legally that I can do to stop her. I am afraid that this guy will send her plane tickets and an uber to the airport.She gave me his name and the city he lives in. I am going to do some sleuthing to figure out who this guy is.What can I do? How can I talk to her in the meantime?TL;DR: My daughter wants to take a two-week trip to see a creepy guy almost 30 years older than her. via /r/Parenting http://ift.tt/2yKplXY