Dallas Morning News -- A framed picture in his parents' home shows Nathaniel Aguirre smiling proudly after completing his last jump at the U.S. Army Airborne School two years ago at Fort Benning, Ga.

The jump signified the end of his airborne training and the start of his military career.

Spc. Aguirre couldn't wait to serve his country. He joined the reserves while still in high school in the Carrollton-Farmers Branch school district and put off plans to attend Texas A&M University so he could sign up for the Army.

"He didn't want to wait four years to go into the service," his father, Louis L. Aguirre of Carrollton, said Thursday. "He wanted to serve."

Spc. Aguirre, 21, was working as an Army combat medic when he was killed Sunday in Baghdad. According to the Department of Defense, he died of injuries suffered when his patrol encountered enemy forces.

He was assigned to the 1st Battalion, 22nd Infantry Regiment, 2nd Brigade Combat Team, 4th Infantry Division based at Fort Hood.

Relatives and friends gathered at the Aguirre family home in Carrollton this week to grieve. Small American flags lined the sidewalk leading to the front door. A memorial of flowers had formed around a bench in the front yard. And a white plastic sheet with a flag border hanging near the front door read: "We will always miss you Nathaniel."

Spc. Aguirre was born Dec. 11, 1984, in San Antonio. His family later moved to Carrollton, where Spc. Aguirre would meet his best friend, Joseph Posenecker, at a church gathering.

Mr. Posenecker described Spc. Aguirre as a leader and a responsible person.

"Always keeping us in line," Mr. Posenecker said of his friend. "Very outgoing and always wanted to be kind of the best at everything."

Family members said Spc. Aguirre had an adventurous spirit. He enjoyed rock climbing so much so that he volunteered at Stoneworks Climbing Gym in Carrollton so he could climb for free. He later became a rock-climbing instructor at the gym.

Spc. Aguirre also was passionate about being a Boy Scout, said his mother, Mary Laureana Aguirre.

"Boy Scouts presented him with structured adventures and learning along with teaching him leadership skills, responsibility, integrity and loyalty that he embraced with such happiness," said Ms. Aguirre, adding that he designated the Boy Scouts as one of his life insurance beneficiaries.

He was also protective of his younger sister, Melissa, his mother said. "Nathaniel has been her model that she's always looked up to," she said.

Spc. Aguirre had been in Iraq since December and was expected to return home at the end of November. He wrote about his life as a soldier and experiences in Iraq on his MySpace.com page. He called himself "Doc," a reference to his role as a medic.

"He was telling his friends exactly what was going on out there," his father said.

But he didn't want his parents to see his page on the social networking Web site. "He wanted to shield us from that," Mr. Aguirre said.

The site included a survey of the soldier's likes and dislikes. Under heroes, he wrote: "I look up to my dad a lot because of all the things he was able to accomplish in life."

And under "Goal You Would Like To Achieve This Year," Spc. Aguirre wrote: "Live through Iraq."

In addition to his immediate family, Spc. Aguirre is survived by his grandparents Laura Garza Brito, Jose Garza and Hope Gonzalez, all of San Antonio. Preceding Spc. Aguirre in death are his grandfather Louis Aguirre Sr. of Dallas and stepgrandfather Fred Gonzalez of San Antonio.

Funeral arrangements are pending. Donations may be made to Boy Scouts of America, Circle Ten Council, 8605 Harry Hines Blvd., Dallas, Texas 75235.