Playwriting

So, yesterday I mentioned a play that I'm writing. I guess I owe it to you guys to let you know what that's about.
My school has a thing called "senior projects", which are (obviously), large projects each student takes on in their senior year. What makes these projects so awesome though is that the students are allowed to do essentially anything they like, as long as they can prove that it's a learning process.
Now, ever since I watched the seniors present their projects in my freshman year, I've been thinking about what I want to do, but it wasn't until last fall that it came to me; I should write a play. So that's what I've been doing over the last few months (even though I'm a junior), I've been working on the concept of the play and getting it down on paper (or word document).
Now, since I started writing this play in November, you'd think that I'd be pretty far, but I've only written a handful of scenes, what with school and all of the other things I listed yesterday (that's why I'm giving myself until June 1st).
My plan is to have the first draft done by June 1st, so I can give it to a couple of teachers at my school at the end of the year to look at for me, then start rehearsals in September. I'll probably put the show on in February of next year, maybe January. I already have a tentative cast in my head (I'm in all likelihood only pulling from current students at my school, just because that makes everything easier, though I do have a few people who aren't at my school that I'd like to be in it if I could make it work). With a cast of six, it hasn't been too difficult to come up with an idea of who I want to play which character, though I'm still debating about the two major male roles (I know the two people I want to play them, but I don't know which guy I want to play which character).
The play is about a group of teenagers who, over the course of the play, and with the help of their mutual therapist, discover that they are a single person with multiple-personality disorder. As the pressure under this well-kept secret builds, an old personality returns from the "grave" in an attempt to drive the others out of their shared head.
What do you guys think? Have I got a concept? So far it seems that I do.

Thing to be grateful for today: Microsoft Word.