If you're looking for any kind of accuracy, the MetaWear won't do it for you if there are people or metal objects in the room. This is because RSSI is a signal-strength-based technology.
Certainly, you can make some sense of your position using RSSI, but any clutter will completely ruin the readings.
If you're looking for accurate indoor positioning you need to use a time of flight system or time difference of arrival system, depending on how you want to set things up and what hardware you have. The Ultra Wide Band technology is part of IEEE 802.15.4. Do a web search for "DecaWave" and/or "BeSpoon" to find modules to do this with. TOF and TdOA will get you close, but you'll still have to deal with limitations and range and complexities of multipath interference.