Please Answer: Major Crisis?

Hi, my name's Nicole, I'm 15, sophomore, I have a dog who's around twelve. I really want another dog, and I've been wanting one for years because me and dad both love German Shepherds. My mom, however, is completely anti-animal and it was hard to get the dog we have now. They said that if I get all A's for this semester in my sophomore year, they would get me the dog. I'm trying extremely hard to achieve this goal, and I've even gotten a tutor that I'm paying for with my own money. However, I'm worried that I'm going to end up with all A's and two B's, but the B's will be in AP Classes, which will weight up to a 4.0. I'm so worried that all this hard work won't pay off and I'll be so close, what can I tell my parents when the time comes, if I didn't make all A's but I've been working very hard and my grades have drastically improved?