Converting a String to a Numeric Date

I need to be able to locate a date in a spreadsheet bassed uppon a user input date. I am looking for the week that contains the user's date. However it seems even if I initialize the value as Date, it still reads the user's input as a string.

Is there an easy way make sure the system automaticaly recognizes the user's input as a date, or is there a way to quicly convert the string to a date?

Thanks!