This smells like a homework assignment ("needs to create a suitable test data"?), but I'll give you some hints.

The limitations on your date string format make it so you can easily parse it with a regular expression. Read the perlre page and about the m// operator, and watch for (capturing), [character sets], and what \d means.

Once you get the numbers out of the date string, it's pretty menial programming from there. (Month names in an array, etc.)