A Texas teenager's skydiving trip to celebrate her 16 th birthday turned nearly fatal when her parachute failed to open and she spun 3,500 feet to the ground.

Mackenzie Wethington, 16, traveled from her home in Joshua, Texas, to Chickasha, Okla., with her father, Joe Wethington, to skydive at Pegasus Air Sport on Jan. 25. In Oklahoma, 16-year-olds are allowed to skydive with parental consent.

"It was her dream," Mackenzie's sister, Meagan, told ABC affiliate WFAA. "So my dad said, 'On your 16 th birthday, I'll take you skydiving.'"

But Mackenzie's parachute failed to open and she spun down to the ground, 3,500 feet below.

Her sister, Meagan, remembers getting the call from their dad that there had been an accident.

"He was like, 'Mackenzie's parachute didn't open up,'" she recalled. "And I was like, 'This is not funny.'"

While Joe Wethington landed safely, his daughter's crash broke her vertebrae, shattered her pelvis and led to internal bleeding.

She is now being treated in the intensive care unit at an Oklahoma City hospital, where officials say she is breathing on her own.

"She just thinks it was her fault because she couldn't reach up and pull the chute," Meagan said.

The owner of Pegasus Air Sport, Bob Swainson, told WFAA that Mackenzie's parachute did open properly but that there was a malfunction and they do not yet know the cause.

Swainson, while declining to comment further, also told the station that Mackenzie did not follow the training on how to activate a second chute that was given prior to her jump.

The Wethington family is now hiring an attorney to help them investigate what caused the accident, according to WFAA.