Idk if this is normal or not

That's normal enough, considering the maturity. I think that's more phosphorus than nitrogen, tbh, because of the sort of darkening, sort of reddening in some areas. And phosphorus is pretty much the main focus of the plant in flowering, as flowers are made for seeds, and seeds load up on phosphorus (from the flowers). All the cannabinoid oils, precursor stuff, and fundamental internal cellular energy (ATP) relies on phosphorus too, and phosphorus is very mobile, with the plant "recycling" it as necessary, sending it from say, the leaves to the flowers. Phosphorus is also related to overall yellowing, so... So, I'd recommend some calmag and a bit of extra phosphorus, tbh. Maybe some extra carbs (like molasses). Considering how dark green some areas look, maturity of the plant, I really REALLY doubt you have nitrogen issues, Here's a song (though you'd probably not like it, it's solid science) about that ATP cycle... www.youtube.com/watch