Chances of getting into Columbia? AP course troubles.?

I'm a sopre wanting to go Columbia. Right now I take all honors courses. I didn't take the one AP course offered, which was World History because I don't feel like I need an AP experience for history. I want to be a dentist and want to major in creative writing. My weighted gpa is a 3.9. My first try at the psat gave me a 176 and that's with no practice. Next year I applied to take honors us history, regular algebra 2/trig, ap chem, ap lit. There was an ap us history and algebra 2/pre calc honors available. I made all the courses but i had to drop ap chem because it conflicted with my italian cl! Now i have to take physics honors. I'm going to take 2 more ap's senior year and introduction to calculus. I'm also going to volunteer at an animal shelter and be in one or two extracurriculars. Since I'm only taking 1 ap course junior year out of the 3 offered are my chances of getting in nearly impossible or not likely? This includes making the waiting list. I would've applied to the honors math if i had known i wouldn't have made the ap chem but I can't change that now. I plan to take a few sat subject tests and am positive I will get past 2000 on the sat's eventually since I'll take it every time it is offered and my english skills are very good. Is there anything I can do? Please, I'm desperate!