How to check MacBook performance

See if any of the following articles can help:

• Maximizing Battery Life and Lifespan - Apple
• About Mac notebook batteries - Apple Support
• Get help with your Mac notebook battery - Apple Support

I'm not sure from your post, but did you purchase a new MacBook or a "new to you" one from a third-party source? I ask as Apple discontinued the MacBook line and the 2017 was their last model they sold.

use ASP ie Apple system profiler found upper top left of menu bar , more info once you get there.

You can go into Applications folder and Utilities folder and launch activity monitor.