Prepare All Kids Act of 2013 - Amends the Elementary and Secondary Education Act of 1965 to require the Secretary of Education to establish a Prekindergarten Incentive Fund from which matching grants shall be awarded to states and, through them, subgrants to qualified prekindergarten providers to establish, expand, or enhance voluntary high quality full-day prekindergarten programs serving children ages three through five.

Directs state grantees to set aside: (1) at least 15% of their grant for quality early childhood development programs for children from birth through age three, and (2) at least 10% of their grant to extend the hours of early childhood development programs to create extended day and year programs.

Requires prekindergarten subgrantees to: (1) maintain a maximum class size of 20 children, with at least 1 prekindergarten teacher per classroom; and (2) ensure that the ratio of children to prekindergarten teachers and teacher aides does not exceed 10 to 1.

Prohibits the use of program funds for assessments of children in prekindergarten or early childhood development programs if: (1) the assessments are used to reward or sanction individual children, teachers, programs, or schools; or (2) a single assessment is used as the primary or sole method for assessing program effectiveness.