Mothers want their kids to do better than they did. It's their job to worry and push you as hard as they can, and you know what? It's a thankless job, because they get called controlling, nagging, etc. Your mother is one of the only people who will encourage and nag you, just because she cares, not because she hopes to gain something from it.
I know it's hard. It's especially hard when she tells you something and it turns out to be true. It's big of you to admit that there's some truth to what she says, and perhaps you should tell her that she was right, and you are trying to make things right, you just need her to give you a little breathing room.
The issue with the applications, as I'm sure your mother has told you, is that there's some things that you don't get a second chance on. When you start a job, a boss isn't going to care about accidents, he's just going to fire you. So when she tells you that you have to follow up and remember things, it's important, because sometimes things you may forget can have a lasting impact on your life.
If you want her to stop judging you, do little things that show her that you are more responsible. Also, you can let her know that you know you've messed up in the past, but you're going to work harder now, and try to stick to that. Once she sees that you are making an effort and following up, then she may let off a little. As you get older, she won't always be this way, and you will be able to get closer to her, but it might take time, since right now all she is concerned about is you doing well in school. Try to remember that she loves you, and is probably scared for you. You sound like you have a good head on your shoulders, and I'm sure you'll be fine.
I welcome your thoughts, let me know if you want to talk more.