Is it normal for a new Mac to have less than 100% battery health?
This happens regularly and we don’t have issues with them at work and often see a pretty wide range of FCC numbers initially. The measurements are precise but not accurate over short time periods. I would track use every three months and if at the 11 month period get a second read by Apple. They will have service notes for the battery diagnostic when new and also at almost a year so that will tell very accurately what the overall lifespan is.
If you haven’t contacted AppleCare and had them run one remote battery diagnostic, do that late January after the rush of holiday help requests has died down. Unless it’s popping a warning or you can’t get reasonable life, there’s no rush to get the first scan done.
Here are some past posts on whether any one measurement is predictive and how to handle end of warranty situations.
I would use that battery hard for a week or two (empty to full) and you’ll know it’s performing or not without needing any special calibration steps that were used in the past.