It's great how many paths there are to this profession. I'm still feeling mine out. I'll admit it, I was one of those 4.0 high school students
o), primarily because I didn't join the school system until high school (I was home schooled), and so when I did get there, I really wanted to do well and prove myself. So I worked very hard. Growing up, I spent my days reading books and running around outside, finding every kind of animal I could--tadpoles from our pond, kittens from the barn cats on the farm, small snakes and baby turtles, etc.--so, like most little girls, I was drawn to vet med. When I hit high school, though, I floundered around a little; I didn't really know how formal academics worked, even though I have always been a self-starter and had done a lot of reading and library research on a variety of topics to supplement the schooling I got from my parents. I did well in chemistry, so I ended up majoring in that (and in German) in college. I'm really not sure why I didn't go pre-med at least from the very beginning, but I think I needed some time to grow.
Fast forward to six months after I finished my German BA (with, at that point, a chem minor): my husband and I moved back to the area we both grew up in, following a failed six month expedition to suburbia, and I got a temp job working in medical information at a local clinic. It was dull, didn't pay particularly well, and by three months in I knew that I had to go back to school to at least finish my chemistry degree and do something more meaningful with my life, since I didn't really want to work in a chemistry lab or teach German, and I realized that I still loved working with animals and had never lost my fascination with science and medicine. So I quit that job and worked for my parents for the summer; by fall I was enrolled in the local university taking my last remaining chemistry classes (just last week I was told my chemistry major was officially recorded at my first university!) and a few bio classes that I needed for my in-state vet school and one or two others. I also got a work-study job at the local humane society, which has only cemented my desire to work with people and animals; from the start I've loved it, I get along well with people there in a customer service capacity (which is a really important skill to learn for vets), and I really enjoy the tech work I get to do, such as physical exams, vaccinations, and so on. Tomorrow I take what will hopefully be the last exam of my last undergraduate class; all that remains is to get some good experience with actual vets (which I am sorely lacking), take the GRE, and apply. If all goes well, I'll join the class of 2014 at the U of MN.
So, really, there's no exact point when I decided vet med was for me, but I think it's been in my genes forever... it just took awhile for that trait to be expressed.