As I’ve mentioned multiple times in this course, your absolute first step towards data science should be to learn SQL.
If you want to learn the basics, go through my SQL for Data Analysis article series...

But if you want to master it, take my SQL for Aspiring Data Scientists 7-day online video course!
It will take you from zero to intermediate level with SQL in 7 days.
In the course you can practice your SQL skills on a true-to-life SQL environment, via exciting tasks and with multiple true-to-life datasets.

LINK: https://data36.com/sql-for-aspiring-data-scientists-7-day-online-course/