At a tough spot career-wise... not sure what to do

As a pilot there is no way you can go from zero flight experience to a job qualified ag pilot in 3 months. That is very dangerous, demanding flying. I know a couple people that do/have done it and it's not something you will get in quickly. 3 months for someone with a commercial pilots license maybe, even then it would be a very intense 3 months. I think you didn't read the fine print of that ad.