Cessna 172 student pilot and supervising instructor reported a runway excursion during landing by student pilot on solo flight. The student slid into the grass; regained aircraft control and taxied back to parking.

Report 1 | Narrative: Was coming in for a full stop landing on runway XX at ZZZ [airport] I decided that since the wind was picking up to not put in 30 degrees of flaps I then came down to the runway fast and touched down and started braking I didn't apply enough left rudder and didn't let up on the breaks and slid off the runway into the grass I was able to get the airplane off the runway and taxi back to parking no damage to the aircraft or any runway lights and no injuries.

Report 2 | Narrative: I was supervising a student solo and the student slid into the grass after the landing. There were no injuries to the student nor damages on the aircraft. The student was able to taxi back to the ramp with no issues.

Report 1 | Synopsis: Cessna 172 student pilot and supervising instructor reported a runway excursion during landing by student pilot on solo flight. The student slid into the grass; regained aircraft control and taxied back to parking.