Yellowing leaves, really worried!

Hi I'm new to this, first time growing.
The plant is about 3 weeks into flowering and the bottom leaves are turning yellow and moving towards to top of the plant..
Will post pics just need someone to tell me how.thanks

.

Bottom leaves turning yellow is a sign of nitrogen deficiency.
Feed her.

thanks so much for the reply!
i'll feed her now.

By the location on the plant, the time into flower and the amount of yellowing.
That's normal!!

DON'T overreact and begin dumping nutrients into the plant that it won't use! When flowering into weeks 3-4 (or as the "stretch" begins to end) the plants needs for N reduce and the need for P&K increase.
Thus you get the false look of N def. The plant is actually, by it's nature, decreasing the uptake of N and pulling it from the "stored" N in the leaves of the plant. This begins at the bottom of the plant and slowly works it's way up.
Continue with a "normal" flowering feeding and restrain yourself from adding "extra" N.
Now then, as a rule of thumb. I don't decrease my N either! And in synthetic/combo grows. I don't boost the P&K till the start of week 4 of flower.

Your plant looks almost spot on for the time frame. Continue on as you have.

ya

I 100% agree with dr who! Just chill be patient.. Look for new growth.. As long as new growth is forming your okay.. Don't be alarmed by the light yellowing that happens on the new growth that's perfectly normal especially during flowering