sorting issue

Hello

I am downloading a report from an ERP the date column in the report will be as shown below but the actual date is 13-12-02
13-12-07,14-01-10,14-01-11,14-01-12(yymmdd)

now i will format the cell as yy-mm-dd so date get changed as per my requirement but if i tried to sort the column it is not sorted properly.

Please advise

example
13-12-2002
13-12-2007
14-01-2010
14-01-2011
14-01-2012

Thanks in advance