In the Alexa App, you can choose from a list of selected wake words. Go to the Alexa app, go to Devices., choose your echo device from the list. Tap the settings gear on the info screen (top right), scroll down to "wake word" and tap it. it will come up with a list of words that Alexa will respond to. Choose one from the list. Sadly, you cannot choose your own. Alternatively, you can give your girlfriend a nickname 😂.
It's likely that a firmware update won't add the ability to change the wake word by voice order if the device doesn't already have that feature and there isn't a way to add it in the settings. You could ask the company that made it if they plan to add it to any future updated versions. For now, you may need to change how you use the device or look into other smart devices that have the wake word choices you need.
