You’ve done really well with it being your first try and having given zero nutrients…..although that should be a lesson to many who over feed the hell out of their plants.
To get her to finish strong and have some good quality buds you will need to feed her now though. She’s beginning to take from what’s stored and will deplete things quickly. Once that happens all the leaves will yellow and die.
You do not need to spend a lot of $$ on a fancy “pot specific” fertilizer…….there’s no difference.
Any fert that is specifically for “blooming” or “flowering” will do the trick.
I would get myself a small bag of dry organic fert , follow the directions on the bag, and spread it on top of your soil surface. Scratch it in a bit and water normally. Based on where the plant is in its life cycle you’ll probably only need one application, maybe 2.
Just make sure the fert is lower in nitrogen and higher in phosphorus and potassium. The 3 numbers on all ferts tell you the percentages of those 3 things. 1st number is nitrogen, 2nd is phosphorus and 3rd being potassium.
A 5-5-5 would have equal parts of all 3, and would be more suitable for the vegetative stage.
You’re now in full flower, so you’ll need something more like 2-8-4……
If you need more guidance just ask. Good luck.