The key phrase is complete picture--as in comprehensive, thorough, and consistent. GPA is a factor in that total picture. Whatever yours is, own it, present it, know the story it tells, and don't make excuses for it.
Let's go back to the self-description you wrote and what your parents and friends told you, and now factor in your GPA. You are beginning to see the outline of the geek that is you. Let's flush it out a bit more with the grades. Answer these questions:
Why is your GPA so high (or low, or medium)?
How did that happen?
What does it say about your priorities?
What does it say about your test-taking or homework skills?
What does it say about your follow-up?
What does it say about the way you communicate to your teachers about what you've learned?
What does it say about your outside time commitments?
What does it say about your most enjoyable subjects?
What does your GPA really represent?
For some people, the GPA says, "Hey, I love working hard and getting all the answers right!" For others it says, "It wasn't always easy, but I have worked very hard and here's proof that I have been successful." Or this: "I took courses that were really hard and wasn't able to put as much effort into them as I wish I had." Or this: "I didn't try nearly as hard as I could have, but you know what? I didn't really care about grades and still don't. I enjoy learning, but I'm not all that excited about doing a lot of the required work."
Whatever your GPA says about you, add that to your description for now. If what it says isn't exactly what you wish it said about you, relax. By the time we finish looking at the complete you, there will be enough of everything else that's good about you to strike a balance and present a pretty good picture of your intellectual self. In the interim, however, continue to think about what are the things that you really like to learn and where you have been successful learning them.
And for however much time you have left at high school, get the highest grades you can get. Work hard!
For more admissions advice on SATs, letters of recommendation, and the personal essay, check out my book, Going Geek: What EverySmart Kid (and Parent) Should Know About College Admissions.