The effects of pre-earth life decisions on our present spirituality

Over the past little while, I've thought quite a bit about what makes someone be born with a clearcut view of what's right and wrong, with a desire to do the right, and someone that sees a lot of grey area, and likes to test the waters.
In this short blog, I won't have time to go into all the details and support I have for my reasoning. I'll pretty much just say what I think and let you agree or disagree with reasons of your own and if you care enough, come ask me about it in person.
I think that someone born here with a really strong desire to do the right thing and with a black and white view of sinning made more decisions than others in the pre-earth life that were correct. So when they were born, they were already further along on their spiritual journey than those others. However, these people can make wrong decisions here and start seeing grey area if they have the wrong people influencing them. They are especially vulnerable when raised in a broken of dysfunctional family.
But when it comes to natural-born desires and views, I believe a large part of that is a reflection of the decisions that we made before we were born.

Getting straight A's

As I've talked with my dad recently about college, I kept thinking and he kept asking the same thing: what is keeping me from getting a 4.0? My grades aren't at all terrible, but what is my excuse for not getting straight A's? I have the brains and the talent. I don't sit in front of the T.V. or computer all day, so what am I doing that's keeping me from getting those A's?
After much thought, I've concluded that it just hasn't clicked with me yet. I believe there comes a time during a person's maturation when responsibility and reliability just become part of one's nature. Homework just gets turned in on time, all the time.
Now this all just sounds like my big excuse for not being the conscientious junior I should be. It's like my out for not performing up to the level I'm capable of. I'm not going to let this conclusion keep me from doing my best to become a better student. But I've thought so much of why I'm not getting that 4.0, and I think this is the reason. I honestly cannot think of anything else.
The problem is, before that mature attribute gets acquired, I still need to get that 4.0. I feel like I'll be wasting all of my God-given talent and ability if I don't. I told my dad (who really wants me to go to Princeton) that I need to find my own motivation to accomplish what I need to to get there. He said no, when I get his age I'll realize that at this point in my life I don't understand what it'll mean to get there and what it'll mean if I don't. I agree. He's NOT the kind of dad that Neal's is in Dead Poets' Society (which I hated, by the way; but that discussion is thankfully over.)
A piece of evidence I have for my maturation theory is the story of a family friend, Bruce Jackson. In high school, he said he was the bottom of his class. When he went to college, he just had this desire to do better and ended up transferring to Oxford for a semester, followed by Amherst and other prestigious schools. But I can't tell my dad that I'll be like this. I have to try my best now. And that means straight A's. If I don't get them, it won't be anyone's fault but my own. In the process, I'll be letting myself, my parents and I feel, my Father in Heaven, down.
Enough of that dumb topic. I hate talking so seriously. It gets me depressed. It was a lot of rambling, too. But I guess I'm glad I got it out.