Solving the Mystery Genre: Independent Study Update

This semester I designed my own course for independent study. Basically I draft up the curriculum, choose course texts and an advisor to look out for me and the college approves it (or not). My study of the mystery genre was heartily approved. So now I'm deep into the earliest offerings of the genre from Poe and moving on into Doyle.
There are so many amazing and important writers and even lesser known writers I wish I could have included, but it's already a pretty heavy course load because in tandem to my readings I'll be working on writing as well and must surrender a mystery manuscript at the end of the semester.
It's going well though, my professor is supportive and a big fan of mysteries herself, so we have good advisor meetings. Best of all, I've had a real break though on my characters I believe. I've always wanted to write several books with this cast and now I can more clearly see how that would work, how the characters will evolve and when we get to meet certain other characters.
Right now I can see four or five books with the core main characters. It's very exciting to be able to plan ahead. Of course, there are certain things to come in future books that I'd like to jump ahead to and start writing now, but I have to keep moving forward and begin at the beginning to get where I'd like to be eventually. I have a notebook full of scenes and outlines for the future, however.
It's my goal, or my pipe-dream perhaps, to have a literary agent by the time I graduate next May. I don't want to wait to start my career as a writer until I finish grad school-- in fact I'm not sure I want to go straight to grad school. And I'm afraid that if I let myself just slip into job that has nothing to do with writing but takes up a lot of my time, that I won't move forward and keep pursuing my writing. I probably will have a full time job besides my writing, but I would like to be something that uses my writing (such as journalism).
Like I said, it's just a goal, but I really want it. I want to be a writer, that's what I'm spending my college career training for, and that's the only thing I really want to do. The only thing I feel like I have to do as a career.