数据库必须“完美”吗？

I'm designing a website to track weight lifting and calories. I've never designed my own database before and I figured I should get is as spot on as possible before I start coding. Every time I think I'm done, I get antsy that it's not perfect. I've mostly fleshed it out in MySQL Workbench but I still have a few questions.I'm designing a website to track weight lifting