I doubt she will listen to you. partly it is being 18 and largely it is being a difficult child. With her academic history there is NO way she should be going away to a college. She simply won't be able to cope. She also won't believe this.
You simply must stop trying to reason with her, in my opinion. It won't work and will just upset you. My great gma used to say that you cannot teach a cow to drink with a straw. It just wastes your time and annoys the cow. While difficult child is NOT a cow, the same thing is going on. Instead of reasoning with her, talk to the counselor at her hs and see what the realistic options are. Then tell difficult child that if she wants one of them that you will help pay for it. Otherwise you wish her the best and will be delighted to watch her prove you wrong as she pays for her choices with money she earns.
She is old enough that she needs a job. She needs to work for her own $ and needs to pay for her own things. She will not ever appreciate anything unless she works for it. Regardless of how mean she thinks you are, it is time for some real world in her life. In the real world you don't get sent away to school when you have not got the grades to justify it, and when you likely cannot get into a competitive program because your academics are not up to it. She also needs to adjust to paying for her own necessities. with-o some regular bills to pay she will likely use any earned money to do frivolous things. We all need some frivolous things, but we also need to pay our bills first.
Supports are available in college, but you still have to be mature enough to go to class when you don't want to, to study when you don't want to, and to avoid problems like drugs and booze and boys. She won't avoid those. She is not going to perform well in college. It is very different than high school and even though supports are there she sure doesn't sound like they will be enough to help her. They are meant for students who have difficulty learning but are willing to put in extra hours learning to learn. If she won't even do a summer program in what she "wants" to make her life's work, no way will she manage to even pass the basic general ed requirements. She is expecting to go into a marine biology class and go down to the ocean to play with the animals. The animals will magically trust her and come to her and tell her all about how great she is. She will be instantly transformed into Jacquette Cousteau with funding sources raining down from the heavens to support her while she plays with the fishies.
There a hundreds of young people who think this. They rarely make it past the first year requirements. Those requirements are heavy on math and science and she is never going to succeed. Not with-o drastic change. But NOTHING will make her see that. If you wanted to be incredibly, undeservedly generous you could offer to split the cost of tuition, books, room and board with her. I am sure that she will not want to put HER money on the line, esp if she pays first.
Have you thought about what will happen if she doesn't go to school? She may decide that if you won't send her to her dream school then she isn't going to school anywhere. You need to have a plan in case this happens. It should include her paying rent and utilities and even leaving your home if she doesn't pay her way. I would put this in writing because there are some areas where you would have to formally evict her if she doesn't leave willingly. It is not because you want to push her out of your home. It is simply to protect you from decisions that you may not want to support. With her grades she may have a tough time getting into any four year university, much less a highly competitive field like marine biology.
(out of curiousity, what were her grades like in high school science and math classes? College is usually far more difficult and with-o the right background she has no real hope of succeeding in college courses.
Anyway, I hope this helps you get a handle on how YOU want to set things up. It is unreasonable to put so much on the line financially for her education if she is not even willing to do summer programs in her supposed field of interest. (FWIW, very few college students graduate with a degree in the field they wanted to study when they went to school. My mother worked on quite a few university committees about this and student retention. Your daughter sounds like she has every risk factor except drug and alcohol problems to indicate problems in achieving her goals for college.)
But when we pointed out to easy child that their schools are better for marine biology, she decided she really wanted to go into art, and logic won the day.
