I second the suggestion of trading the Midget Mustang for the RV. I would love to own a Midget Mustang to fly around, it would be a lot of fun. But it's single seat, which means I can't share that fun. So it could never be my first airplane.
Also, as you don't have a license, you're going to find it extremely painful to keep looking at that "almost ready" Midget Mustang sitting there until you get your license, and then even when it's finished it would be unwise for that to be your first plane. It's very short coupled, and you won't have an instructor with you to check you out.
A much better idea would be to finish the -6 (you won't make any mistakes you can't fix, after all, you're in the Aviation Maintenance program, right?), and then learn to fly in it. That won't be as easy as learning in a Cessna, but I doubt it would be significantly harder either. What it will be, is a *lot* more fun than learning in a Cessna.
Just my $0.02.
