Battery capacity
Is it still healthy battery if it is decrease into 99% battery capacity after 7 months old?
Question marked as
Battery Health & Performance
Your battery health is fine and is undergoing normal usage. You should change out the battery once your Battery Health reaches below 80% which will take over 2 years to reach under normal usage. Until then enjoy your iPhone.
Here is some more reading on an iPhone battery and its performance ➔ iPhone Battery and Performance - Apple Support
Axel F.