Age 18, female, is this AGA on the top of my head? I see miniaturization (Photos)

I appreciate your concern. That would be a big mistake to think a few miniaturized hairs equates to a diagnosis of androgenetic alopecia. Even the healthiest of scalps with no androgenetic alopecia has some miniaturized hairs. It’s not uncommon for about 5-10 % to be miniaturized. The proportion will even be a bit different in different regions of the scalp. Also fro every 8 thick hairs on the scalp, about one will be a tiny vellus hair. That’s what we see under normal circumstances. Also, lots of conditions can cause hairs to appear miniaturized. Androgenetic alopecia is famous for doing this but it’s not the only one. Alopecia areata, psoriasis, highly inflammatory seborrheic dermatitis, tractions alopecia can all affect hair caliber. Be sure to see a qualified specialist if your concerns continue. What really matters now is how your density in the middle and crown compares to the back of the scalp and how your central part and back part change over time.

I can't tell from the photo if this is androgenetic or telogen effluvium. a photo of your crown from a few feet away would be more helpful...Also the history of a rapid hair loss would favor telogen effluvium..Family history would help also...Does your mother or dad have moderate thinning?
When you run your fingers thru your hair do you get alot of hairs or very few to none. Getting alot would point more toward telogen effluvium. Was there a medical event 3-6 months ago like surgery? This would point toward telogen effluvium. Using topical minoxidil or a compound with minoxidil and dutasteride would also help.

Hair loss types fall primarily into 2 main buckets: acute and chronic.

The acute types usually result in hairs being pushed out from mental or physical stress. Generally all hairs in a follicle are pushed out at the same time from the affected follicles. When this happens you would see under the microscope empty follicles where there are no hairs. Unfortunately your pictures are only of very small areas of your scalp so hard to determine if this has happened anywhere. Telogen Effluvium is where this happens on a large scale and many of your follicles are affected. Alopecia Areata is where this happens in small patches or circles.

One of the chronic types of hair loss is Androgenetic Alopecia or Male/Female pattern hair loss. This is characterized by miniaturized hairs. I do see some of those in the pictures you posted. However, its important to remember that each hair goes through a growth cycle on average for 7-9 years, it then falls out and is replaced by a new baby hair which over time grows up to be a mature long hair. This does mean that a small percentage of your hairs will be small baby hairs at any point in time.
The thing to look for is whether the hairs are miniaturizing vs growing.

The other thing to consider is what is causing the hair loss. It is actually not possible to effectively treat hair loss without first treating and stopping the underlying causes. And I say "causes" because particularly for women there is generally more than one thing going on, and unless we find and treat everything going on the treatment will not be effective.

My recommended approach is to seek out an accurate diagnosis from a hair regrowth expert who understands molecular biology and who will use blood tests to understand all the different factors that are contributing to your hair loss.