Android 13 could arrive a month earlier than Android 12 did
Google has outlined when stable Android 13 builds should be ready, with the operating system having now reached Beta 4.1. For context, Android 13 gained Platform Stability status with Beta 3, with Beta 4 serving as Android 13's release candidate build. While Google has not made a formal announcement yet, 'Android 13 Security Release Notes' provide some clarity.
Specifically, the release notes contain the following sentence:
Android 13 devices with a security patch level of 2022-09-01 or later are protected against these issues (Android 13, as released on AOSP, will have a default security patch level of 2022-09-01).
Hence, it seems likely that Google will release Android 13 to the Android Open Source Project (AOSP) in September, although not necessarily on September 1. Incidentally, a September release for Android 13 would be eleven months after Android 12 reached AOSP. Ultimately, Android 13's development has not been quicker than Android 12; Google just started its Beta Program earlier this year.
It is worth noting that Google may take another few weeks to bring Android 13 to Pixel smartphones. As it stands, all Pixel smartphones from the Pixel 4 and Pixel 4 XL should receive Android 13. Presumably, Google will confirm release timings for Android 13 on Pixel smartphones when it issues the OS update to AOSP.