you can still take your cuttings in flower if you want but as was said it will take about 2 weeks to root and revert back to veg state so if you dont mind the wait for them to root then carry on it will be ok i have done this many time i have even taken little buds from the bottom of the plant and cloned them . or you could even leave some little buds on the plant after harvest and reveg the whole plant for cuttings .this is what i have just done after having the same situatoin that you are in but idf you want to take the cuttings take them.be safe the postman.