battery

Hello, I bought Iphone12 on January 30, 2021. I have a question about the battery. Namely, from the beginning of the purchase to about 6 months of use was 100% of the battery after quickly fell asleep first to 99% and then 98 and 97. The moment given a couple of days ago was 98%, and became 97%. Is this a problem? And do you need to contact the service center?