You're concerned about your work, we totally get that. Have no fear though, your projects will move with you. If you decide to upgrade from a Team Trial to Team Paid, Starter to Team, or Team to Enterprise, it doesn't matter, your project(s) will move with you.
If you were on a starter trial on trial.dc.irise.com, there's a little more work involved, but you won't lose your work in this case either. Just follow the steps in this article, and you should be good.
If you need help, just contact us in Support.