Conditional Formation based on Month

I have a field where the month is written as text
I would like to highlight row whose month column has passed

My conditional formating code is:

=MONTH(1&$F3)<MMONTH(TODAY())

The problem is that it highlight all the blank cell because it sees them as 01.
Any ideas how I could get it to highlight only those who month has passed while leaving those that are blank unformated.

Thank you for your help.