I owe a 2016 VW Jetta and have been using regular oil, not knowing it needs synthetic oil. Could this cause the EPC and engine light to appear?
You should still be in the warranty period and no the oil is not turning your light on.
If you are changing the oil according to the maintenance computer but using oil that does not meet the required standards, sludge can develop. Dirt particles or sludge can cause variable valve timing control valves to stick, this will cause the check engine light to turn on. This is speculation however, you need to have the problem diagnosed.
Start by having the codes read. Auto parts stores in most states will do this for free.