Leaves at bottom are turning yellow and falling off?

Recently, I put my two plants into flowering. Both of them have had yellowing starting at the bottom going up. Large green bottom leaves would start to turn yellow, and within a week, be completely yellow. At that point, I would remove it because the plant was using energy to heal it. Once I did that, the leaves above them would start to do the same thing, like a domino effect. I am 5 weeks into flowering, and the leaves start half way up the thing because I removed so many already. What should I do? Should I remove it as soon as it starts to turn yellow? Should I just let it fall off by itself? Is this whole process natural? Thanks.

How many weeks in?

After the first month of flowering a photo you should start to see some yellowing at the bottom and this is normal due to low N and also because of almost no light hitting the bottom.
Never yank a fan leave off unless its brown and wrinkled to the point where its dangling and you just touch it and it falls off.

Yah let those leafs fall off on there own.