Battery health

Battery Health & Performance 

Your battery health is fine and is undergoing normal usage. iPhone batteries, like all rechargeable batteries, are consumable components that become less effective as they age. 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.  

That's fine. Apple's nominal rating is 80% battery health after 500 complete charge-discharge cycles. After 1.5 months it wouldn't be unusual for the battery health to be reported at 99%. Just keep and eye on it.