my husband and i have recently started bike riding again, we have both mountain/trail bikes and hybrid road bikes. a friend who is a much more active rider talked us into signing up for a 26 mile casual ride in downton san diego called Bike the Bay. to say we are unprepared for that ride coming up on us this weekend is probably a gross understatement.
we will be going anyway, hopefully with another few practice rides between now and then, but it is supposed to be a fun ride, not a race so i think it will be ok. 
I have faith in you both. Just go enjoy yourselves!