I want to know what is the average response time of an app if the database has millions of records.

I built an app with Golang and MongoDB, seeded database with 20 millions records as shown in the image below which took about 49 minutes. And an API with multiple MongoDB Aggregation Pipeline stages responded the data pretty fast (<500ms) does this mean that this is an average result! and that the app has to be tested with 100M+ records in order to actually see the true performance?

Performance Test Results using JMeter.

Criteria: 600 requests made in 300ms
Result: Success
Fastest Response Time: 62ms
Slowest Response Time: 282ms