Safety at Big Bend National Park

I would be way more worried in Odessa.

Between the remoteness from both the Texas and Mexico sides, multiple law enforcement agencies, and border checkpoints on the few roads from the park up to Hwy 90, Big Bend Nat'l Park is very safe.

No problems we were there this February for two weeks - one of which was at the Rio Grande Village RV Park inside the park right on the Rio Grande
We took the row boat over to Mexico and had a great breakfast there

When I was there a few years ago, talked to a BP agent about illegal activity in the Big Bend area. He said it was rare because it is AT LEAST a 3-day hike across the desert to any civilization.

I concur with the others that you will be safe at BBNP. The only issue I have heard lately is that the park has closed the popular Lost Mine Trail due to increased bear activity. It is good to see that the bears are continuing their return and that the park service is keeping everyone safe by reducing the possibility of interaction.

We've been to BBNP several times and I think the area is isolated on the Mexican side too. I didn't see any signs of roads over there and few buildings. And I don't recall seeing any people either. There isn't much Border Patrol activity either. We felt perfectly safe.

Been doing Christmas Holiday camping at Big Bend for about 15 years now. Very safe, never had any problems. The territory in Mexico is also a National Park I believe, and except for one or two small villages there is very little for 100's of miles inland. The US Border Patrol has a good working relationship with the Mexicans too, any any minor issues that come up are quickly resolved.

Unless your daughter has specific reasons, I'd not worry about it.