No preflowers shown at all.
The ones you want to see will look like tear drops nomally with a pair of hairs sticking out. They normally form at the top of the plant first. It is looks like a ball on a stick it is probably a male.
You can take a clone and flower that to be safe. Or put the whole plant into 12/12 and then back into veg after you tell if it is a female or not.