If it seems like a big moment, it's because it is a big moment. Once you've made your work publicly available under a CC license, well, you've made it publicly available. Although you fully retain your own rights to the work, you are explicitly saying that the material is legitimately yours to license and may be shared, used, modified as per the license you've chosen. Once you have made your work available under a CC license, there's no going back.

Here is a list of things to double check before you expose your masterwork to the world:

The material is yours to license.
Any such included works are appropriately attributed.
The license that you have chosen best suits your purpose.
The license that you have chosen "plays well" with the licenses of the works, if any, that you have included.

When it comes to quality, there are a few additional things to double check:

Educational best practices are built into the work.
If applicable, "gaps" have been left in the work for users to fill with texts of their choice.
The material is as accurate and articulate as you can make it.

We've discussed most of this at length, but a bit more information in the way of choosing a license is in order before we sign our souls away.