Date column in a!gridField() sorting correctly by month/day, but ignoring year

I have a paging grid setup that allows users to sort records by a "date created" field.  

a!gridTextColumn(
    label:"Created Date",
    field:"createdDt",
    data:fn!text(local!dataSet.data.createdDt,"MMM DD, YYYY")
)

When sorting by the date column in the grid, the dates are ordered correctly by month/day, but ignoring the year column. (i.e: Ascending order: {Jan 22, 2017; Feb 15, 2015; March 9 2016; etc}, should be: {Feb 15, 2015; March 9 2016;Jan 22, 2017}).  I know paging grids only accept image and text column definitions, so is there anyway to enforce the correct sorting for a date value in a text column?
Thank you in advance!