You lucked out man!
As a former firefighter, I’ve seen a lot of houses go down. You were lucky. I take it the FD was there already, protecting your house?
Depending on your surroundings, the fire could be smoldering underground for days. I would keep a close eye on things, especially on the edge where the burned meets the unburned. The FD is most likely doing this, but sometimes they don’t do a perfect job; I wouldn’t bet my house on it!
100 acres? Holy cow! How many do you own?