A good place to start on finding demographic data is the U.S. Census Bureau. This resource allows you to search the data collected by the agency and you can explore the data, as shown in the tutorial video. Watch it to learn how to use the data portal.
Note that this resource offers more than just demographic data, which can help you explore other aspects of the Austin area.
If you look up the demographics of Elgin and Georgetown to see how much of the adult population has at least a Bachelor's degree, what might that tell you about those two areas?
What conclusions would you draw if you also looked up how much of the population in those two areas has health insurance?
The data portal from the U.S. Census Bureau is not the only source of data you can use to research demographics. Other resources exist and some are listed below. It is important to understand that not all resources are the same and some can fulfill your information needs better than others. The best way to learn which one works best for you is exploring them.
This resource, provided by the city of Austin, collates data and publishes demographic profiles, in addition to other materials such as maps, reports, and more. While Austin-centric, this resource also has some information about the metropolitan area.
This organization collaborates with the U.S. Census Bureau to collect, interpret, and shares demographic data for the state of Texas. Their website has reports for state-wide as well as more centered on Greater Austin.