During a personal flight, the student pilot, with a passenger, attempted a takeoff from a private grass airstrip that was 2,000 ft in length. The runway had an upward slope during its initial 1,000 ft with the steepest slope occurring during its initial 700 ft. A witness stated that the engine sounded normal and the airplane’s acceleration was slow during the uphill takeoff roll. The airplane lifted off about 900 ft down the runway and entered a nose-high attitude followed by what appeared to be an aerodynamic stall. The airplane descended, impacted terrain, and sustained substantial damage to the fuselage and both wings. The pilot stated that the accident could have been prevented by extending the wing flaps after considering a change in density altitude. The Airplane Flying Handbook (FAA-H-8083-3C), Chapter 6, stated that the use of wing flaps is predicated on whether a takeoff is from a short/soft field. Two of the student pilot’s flight instructors stated that they advised the student pilot not to use the accident airplane to learn how to fly. Both flight instructors used a Piper PA-28-140, in preparation for the student pilot to fly solo. One of the flight instructors said that a Piper PA-28-140 was more appropriate to learn in, and the student pilot tended to aggressively get the airplane airborne during takeoff. There were no pilot logbook(s) that were provided showing that the student pilot had current student pilot endorsement(s) to fly the accident airplane and to fly to/from the airstrip. The pilot stated there was no mechanical malfunction failure of the airplane that would have precluded normal operation.