To fertilize or not to fertilize that is my question

Hey I have a nice big girl on my hands about 4 feet I would say and she been grown all natural I didn't do much but plant it in the grown but now I have noticed that it is budding so I want to know if I can add some flowering fertilizer to make bigger nuggs or would it be to late since it would be the first time adding fertilizer.

Of course it would help, it sure wouldn't hurt Make sure it's rich in P&K.