You're technically correct of course, but remember your audience (important pedagogical consideration). These are new grads that think git and github are synonymous. A slightly less technically correct but grokkable explanation is probably a better stepping stone toward arriving at a more correct understanding. You're description is abstract, which is harder to grok for most people than a concrete example. If you want to be more technically correct and therefore launch into a discussion about DAGs you're also not going to teach them anything.

Note: there are always exceptions, and a good teacher adapts to the audience. I'm referring to the very general case, not the exceptional case.