Koutsoumbaris, who attended University High School in Palm Harbor, was named to the All America First Team.
Roberts (Lake Gibson High School) and Stevens (Mulberry High School) made the All-America Second Team.
In all, 48 players comprised three All America teams.
"Stephanie, Maggie and Rose exemplify the type of player and person that we want to be a part of the softball program here at Polk State," said head coach Jeff Ellis.
"They all had record-setting careers, and we are very proud of them. Stephanie is our third player to earn First Team All America honors while Maggie and Rose are the program's first two-time All Americas. They left a lasting mark on our program that will never be forgotten."
The efforts of Koutsoumbaris, Roberts, and Stevens helped the Eagles (44-14) win the Suncoast Conference championship and reach the FCSAA Gulf District final in 2014 for the third time in the past four years.
The All-America selections followed record-breaking seasons for the three sophomores.
Koutsoumbaris, a catcher and outfielder, tied for most RBI in a season (73) and ended her career first in RBI (143) and third in hits (170), doubles (41), home runs (19), and batting average (.424). She was also named FCSAA State Player of the Year.
Roberts, who moved this year from third base to first base, hit the most home runs in a season (15) and tied for most RBI in a season (73). For her career she finished first in doubles (43), home runs (25), and batting average (.463), and second in hits (173) and RBI (127).
Outfielder Stevens set the mark for most stolen bases in a season (64) and a career (126). She ended her career first in hits (181) and runs scored (128) and second in batting average (.440).