Looking at other 1900 nickels coins in that condition are Good and possibly even very good depending on the person listing the item. But for near certain not F or fine. So its not the absolute worst, but its not the best. But the coin is 126 years old so its seen some usage. I used to live in a small town with 2,000 people in it, my uncle lived in one w a population just over 100+ these are the best places to spend time collecting coins.
On the front (obverse) of this coin u can usually see a headband w the words "LIBERTY" on them. These higher spots on the coin are what wear off first. Hope this is helpful, thanks for posting!