Are you even a smoker, OP? Because from what I'm reading it just seems to me like that you really like botany, not that you're smoking marijuana. It makes a huge difference whether you're majoring in botany because you smoke marijuana, or because you like to work with plants.

I really liked plants as a child, too, and I ended up going into biology. I tried to get into agriculture/life sciences at a very competitive school and was rejected, so I accepted an offer at another competitive school for my current major. Despite what many people think, agriculture and these kind of industries can be seriously difficult and potentially lucrative. I can't see the marijuana industry being easy to get into at all so if you are a smoker and considering this path for that reason, I recommend you don't follow through with it.

However, it you really do enjoy botany then I would suggest that you talk to your parents about the agricultural parts of it. I would also imagine a minor would be very beneficial. Let your parents know if you're planning on a minor in business, or maybe something like pharmaceutical science if that is offered? I think a good discussion with your parents would show that them that you have planned for different aspects of the industry and not only the "I'm growing weed" part.