waiting until the cutting is firmly rooted might be a good idea, if it dies, you'd have to take another cutting and the plant might not be showing flowers yet but, internally, i believe it would have started to change, chemically, hormonally. i am no expert but, it would seem to me to be safer to take at least 2 cuttings before you flower so if one dies, you have another.
also, how old are your plants? you don't mention that in your original post so, maybe, the plants aren't ready for flowering anyway.
shoot us some pics so we can help you more.
anyway, toke amongst yourselves

bozo,
peace, love, dope