Prior to enrolling at the University of Connecticut she played for Mater Dei High School in Santa Ana, California.

Mosqueda-Lewis was named the 2011 State Farm/WBCA High School Player of the Year by the Women's Basketball Coaches Association.

[4] Mosqueda-Lewis and her Mater Dei high school team was invited to the 2011 Hoophall Classic, held in Springfield, Massachusetts.

However, Mater Dei hit free throws, and held on to win, behind a team leading sixteen points from Mosqueda-Lewis.

In 2015, she broke the NCAA Division I record for career 3-pointers, during UConn's 91–70 regional final win against Dayton.

[15][16] On March 17, 2011, Mosqueda-Lewis was attending school as usual, and heard an announcement that there would be an assembly to honor the girls and boys basketball team.

The announcement of the award compared her to Maya Moore, noting that both players won a championship at the Nike Tournament of Champions, both won a Nike National title, both were ranked the number one prospect in their class, but Mosqueda-Lewis led her team to consecutive number one ranking among high school teams, a feat not accomplished by Moore.

The team competed in the 2010 FIBA U17 World Championship for Women, held in Rodez & Toulouse, France during July 2010.

[20] Mosqueda-Lewis was selected to be a member of the USA Basketball U19 squad, competing for the U19 World Championships in Chile.

The USA took an early lead in the semi-final against Brazil, and went on to win to qualify for the gold medal game.

In the gold medal game against Spain, she was the leading scorer with 15 points (tied with Elizabeth Williams and Stefanie Dolson).

[21] Mosqueda-Lewis, along with teammate Bria Hartley were two of the twelve players selected to be on the team representing the US at the World University Games held in Kazan, Russia in July 2013.

Crystal Bradford scored a basket with 134 seconds left ant he game to secure a 79–78 victory.

[25] Mosqueda-Lewis had enough self-confidence to ask for player number 23, worn most recently by Maya Moore, a star and UConn and an eventual #1 pick in the 2011 WNBA draft.

Mosqueda-Lewis notched 32 double digit performances and registered 14 consecutive double-digit games to end the season.

Mosqueda-Lewis scored a career-high 32 points, and tied a career high by burying 12 3-pointers, in UConn's 85–51 victory over USF (March 2).

Mosqueda-Lewis posted three double-doubles and one triple-double, a 20-point, 10-rebound, 10-assist effort in the Huskies' NCAA Second Round victory against Saint Joseph's (March 25).

She was selected to the American Athletic Conference All-Tournament Team after averaging 14.7 points and shooting 47.4 percent from 3-point range.

Mosqueda-Lewis continued her strong finish to the season by averaging 17.0 points, 8.3 rebounds and 3.9 assists per game during UConn's six-game run through the NCAA Tournament.

[29] Later that year she broke the NCAA Division I record for career 3-pointers, during UConn's 91–70 regional final win against Dayton.

[13] She is now the NCAA Division I record-holder for made three-point attempts, ending the season with 398 threes, and surpassing the prior record of 392, held jointly by Laurie Koehn and Heather Butler.