Speaking as a 16 year-old, who started posting here as a 14 year old, this plot is kinda.. Shallow.
Mate, I'd advise against the release of your first campaign, and I'm saying this as someone who did what all people stereotypically do when they see FRED for the first time; try to FRED some campaign that ties up all the loose ends of the story, rescues Bosch, and puts the Shivans away for good. I got 'till about the 17th mission, I believe. But I didn't once (seriously) think of releasing it. Why?
Because I knew it would be fraught with bugs. I knew it would have gaping plot inconsistencies. I knew the characters would be 2D. I knew it would make little sense to someone other than me. But I did it anyway, because I wanted to
learn about FRED, I wanted to
learn how to tell a story through the medium of Freespace, and I wanted to
learn what one could do with FRED.
Less than a year on, and I still haven't learned how to tell a good story in Freespace, I'm still mesmerized by the Hero stories I grew up with, and I still love huge battles that add little or nothing to the story. But I can tell you, I know a helluva lot more about FRED than I did when I started out. So I suggest you take this campaign in your stride, but take a long hard look at it before you contemplate releasing it. I promise you, you'll have learned many great things when you're done, and I also promise that you'll look back on this in a year or so, and wonder "Why the **** did I do that?" Or something related when you play through the campaign, after a good crash-course in FRED.
No-one makes a good first campaign. Hear me? No-one.
But guess what? Everyone learns. I suggest you do the same.

Play some of the 'famous' user-made campaigns, like Derelict, and Blue Planet. Learn from people like Darius and Blaise Russel, open their missions up and take a look at how they do things. I guarantee you, you'll find a new way of doing something, and hey, it might be better than yours.