It's hard to tell what's going, on as far as pre-flowering is concerned, from the pictures.
Trimming fan leaves is more of an indoor thing, the sun is very powerful so there is not as much need to worry about light penetrating to the inside when growing outdoors. Trimming fan leaves can also shock the plant, shock can sometimes induce pre-flower.
If your plant was started outside under natural light cycles, then it is normal for plants to show sex at this time of year, meaning you will see a tiny calyx (or pollen sack)appear at the spot the where the leaf/branch meets the stem, that is normal, what you don't want to see is a cluster of calyxes(or pollen sacks), that's pre-flower.
If it is pre-flowering and was started under artificial light using longer than current natural light cycles, it may take a while to stop flowering depending on how far into flower it is, but it will eventually pull out as the days get longer.
If it was started under natural light cycles then it is probably just showing its sex and it will be fine.
A good way of determining if a plant is truly going into pre-flower is to pay attention to the finger count of the leaves coming out. So say you have seven finger leaves coming out, look at the new sets of leaves coming out, if the new leaves forming at the very tips are all five and/or three finger leaves, then your plant is pre-flowering, if they finger count of the new leaves coming out is holding steady, or preferably increasing, then your plant is not flowering.
Descending finger count = flowering, increasing finger count = veg.