Extremely knowledgable? I don't think anyone is extremely knowledgeable in the area of drugs and diseases...otherwise there would be cures for all the nasty diseases out there and perhaps drugs wouldn't have unexpected negative consequences because people would know about them and anticipate them...there's always more to learn and that's what post-secondary education is about...it's a lifelong learning process, that's why people devote their lives to studying one particular molecule part of one insignificant biological pathway...
So to answer your question...yes it really is worth it to go into pharmacy. Pharmacy is more than just sitting behind a counter, dispensing drugs all day and has great potential.
Anyways, you're only in grade 12, you need to focus on getting into university first and then start to think about what you want to do...keep your options open, because things can change coming into university. Many peoples grades fall significantly from high school to university because it can be a difficult transition, while others are lucky. I've seen many people I know drop out after 1st year because it is difficult and upper year class sizes go down from about 1000 in first year to 400-500 in upper years. 4th year classes end up having 50-60 people, but that's a different story.
Anyways, point is 1) keep your grades up 2) pharmacy is a great career 3) keep your options open.