Baby Shower - Save the Date?

We're doing a coed backyard BBQ baby shower in October and I was thinking of doing a save the date Facebook event and invite everyone that will be getting an actual invitation. I don't want to be tacky, so would a Facebook save the date be weird?
I figured FB would help remind people about the event coming up, that way people don't forget to RSVP or to attend. Plus it gives an alternative way to RSVP.