There two major species of Luffa and Many varieties. some varieties are daylight sensitive and will only fruit on deceasing daylight in late summer-early fall. Most of the time Chinese okra refers to the species angled luffa whereas the smooth luffa is simply called vine okra. Not allways the case however so I have no idea what type or variety you are growing. Evergreen has about the best collection in one place. http://www.evergreenseeds.com/edibleluffa.html

I am growing angled and it has FINALLY produced both male and female flowers. I will probably not get many before fall, but know for next year to start even earlier indoors. It is amazing how they bloom in the evening and the moths find them-the flowers have a strong smell.

When I was in Maryland, I grew luffa, but do not have enough time to get fruits.