There is supposed to be a 2 year gap between Matt and Shelby moving into the house and what we are seeing being captured on the found footage. When Matt and Shelby are talking, remember he says that he hasn't felt human or hasn't felt like himself or however he worded it for the last two years. This is in the context of him talking about how the house took something from them and ruined them.

2014, 2014, 2015, 2016.
Less than forget. But more than begun.