Trimming

I'm a first time grower as well. I'm near 4 weeks from the flip and she's losing bottom leaves from my own mistakes. Being a first time grower I recommend saving trimming for another day when your comfortable knowing how the plant grows and acts.

 

 
Trimming should be done on harvest day. It involves cutting off the leaves leaving the bud to hang up and dry.
 
It's common practice once you have switched to 12/12 to clear the lower growth on a plant so you don't end up with a ton of scraggly crappy bud at the bottom that's a nightmare to trim on harvest day. 
 
De-foliating involves removing leaves for no reason. Only idiots that have no understanding of biology do this and I do not recommend it 

 

Yea, what he said.

It sounds more like what you are referring to is pruning or defoliating. Removing branches, as gold sad has its benefits if you know what you are doing. I also agree that removing leaves, or defoliating is not a great idea but there are some who swear by the practice.

For your first grow or two, I recommend just growing the plant naturally if possible. Once you see how the plant grows, and how buds develop you will better understand how to train and prune the plant much better.

 

I too thought of "defoliating" and I am still thinking about it when my plant is in flower for about 2 weeks now. there are some nice huge fan leaves on my girl, and these leaves I think are blocking most light to the lower leaves under the fan leaves. I havnt defoliated them though. It is as well my first grow and I just want to learn right now, possibly in my next grow i will try topping, to try and do a small scrog with 2 plants.

this was a few weeks ago 2-3

this is a recent showing some of the underside