I recently had this conversation with my girlfriend. Like you: I frequently talk to her about Bitcoin, crypto and technologies. She is not the most technically savvy person but I do my best to explain things in terms that can be understood be those that are less technically inclined. It's best to keep things simple at first then provide more elaboration if interest is shown. You could try to start with the following:

Explain that Steemit is a social platform that rewards contributors for good content by paying them based on the reception by other users. The payments are locked into the platform for an extended period of time but can be used to up-vote other content. The value of the payments can fluctuate over time based on the success of the platform. This creates a self-reinforcing cycle where good content writers are incentivized to keep creating content and to up-vote other good content to make the platform a success. In a sense, the users and contributors are all shareholders of Steemit and are beholden to each other to help increase the value of the platform. Steemit works similar to other platforms and demoing it will go a long way to understanding.

Obviously the above does not explain Steem, Steem Power, powering up (or down), and blockchains. These are all much more technical aspects and can be picked up on once a user has gotten a handle on the platform. The important part is that knowledge of these things is not required to get started. A user simply has to sign up and start contributing! This low barrier of entry into the platform is a huge boon and is what will draw people in.

So... don't drive her insane with the technical aspects. Just ease her into the platform and the rest should take care of itself.