In her two AJGA appearances in 2016, Cooper won the AJGA Kansas Junior at Buffalo Dunes and finished second at the Bishops Gate Golf Academy Junior at Horseshow Bay. In 2015, she earned wins at the Bishops Gate Golf Academy Junior at Horseshoe Bay and the KPMG Stacy Lewis Junior All-Star Invitational. She was also a member of the victorious 2015 PING Junior Solheim Cup U.S. Team. Ranked No. 16 in the Polo Golf Rankings, the Montgomery High School junior earned first-team Rolex Junior All-America honors in 2015.
| Rank | Event | R1 | R2 | R3 | R4 | Total |
| 1 | 2016 AJGA Kansas Junior at Buffalo Dunes | 69 | 68 | 74 | 211 | |
| 2 | 2016 Bishops Gate Golf Academy Junior at Horseshoe Bay | 75 | 74 | 70 | 219 | |
| T12 | 2016 Kathy Whitworth Invitational | 75 | 74 | 149 | ||
| T12 | 2015 The PING Invitational | 82 | 76 | 77 | 235 | |
| T16 | 2015 Junior PGA Championship | 77 | 75 | 74 | 75 | 301 |
| T33 | 2015 U.S. Girls' Junior Championship | 70 | 72 | 142 |