I’m currently a senior in high school and I have a sinking feeling that I’ll do very poorly in college. People have always said that you’ll do well in college if you’re ambitious and driven to do work - that is not me. I have a GPA that’s hovering above a 3.0, but I wouldn’t exactly describe myself as a dedicated student. I do all my homework, but I never put much time or effort into it - I just finish it as fast as possible so I can get on to doing what I want. In terms of tests, I don’t usually study, unless it’s finals, but I usually do pretty well on tests anyway because of my good memory and innate intelligence. The only time I ever get a bad grade on a test or in a class is if I don’t understand the material right from the start - the classes I understand and enjoy I always do really well in.
I know all this stuff sounds really negative like it’s guaranteed that I’ll flunk out of college, but there are a few things that give me a glimmer of hope. For one thing, I NEVER procrastinate - if I’m told I have to do something, I always feel like I have to get it done as soon as possible and as fast as possible. Also, there are some subjects that genuinely interest me, such as Writing, English, History, and Geography - in those classes, I don’t mind doing all the work. For instance, in the Creative Writing class I just took, I got an A+ because I went above and beyond and truly cared about doing my assignments. Do you think I’ll do well in college?
I think you’ll be fine! College is TOTALLY different than high school. honestly, just stepping foot on campus your first day, you’ll probably start to take things more seriously. You’ll be great! No worries! 
You’ve already evaluated your weaknesses and strengths, so now that you know what you need to work on, you can start moving forward. If you know you don’t put effort into your homework or study for tests, you can decide to change that for college. It’s all about developing better habits, and I see no reason why you couldn’t work on that for the next four years. If you want college to be the same as high school, keep your bad habits. If you’d like to do better and feel better, it’s up to you to change. Hope that helps!
You sound like what I would call an anti-procrastinator, do the bad things right away, even if that means rushing, in order to get to the good stuff. Do you also eat all the things you don’t like on the plate first and save the best for last?
You seem to know your weaknesses and the above posters have great advice. One trick for your rushing problem is to not only try to think more in depth about something, but actively give yourself a set or MINIMUM amount of time to spend on something. Say for instance that you have ten math problems to do. Make yourself spend two to three minutes really working through every step of the problem. Just an idea.
Plus, in college you will probably not have to have the breadth of classes that you had in high school. After the first few semesters, the classes will grow more and more specific to your major, so they are more likely to interest you, so you will probably be more motivated to work hard and do well.