I think until it starts erupting, DPS will operate as normal. Even after the eruption happens, it would depend if the activity and any ash cloud will affect the air space around the airport.

I would imagine airlines and insurance companies would not start pro-actively approving rebookings and destination changes until then. The worse case scenario would be for you to be in Bali, have it erupt and then get grounded there with no flights out.

I'd give them a call to see what they say. You have nothing to lose at this point.