How exactly do you know if you have been accepted?
I think the answer to that has varied over time. Lots of folks here mention having gotten e-mail, for example, but I got none.
I got my model Y about three months ago with paid-for FSD, and found and clicked the button to request beta within days. When I finally got into Beta a couple of weeks ago, I got an app message alerting me to an available software update, and requesting my permission to take up to a half hour to install. This had happened before, and did not mean Beta.
But after the install several things were clearly different:
1. Right when I got in the car, there was a screenful of legalese with a big red picture above it, giving terms, conditions, and warnings about Beta participation. I'd not seen that before.
2. Right away, just when progressing down my driveway and local streets, the left-screen looked different.
a. The road edges now had a broad red line.
b. The screen displayed lots more other vehicles
c. The images for other vehicles were more detailed and more varied.
3. I'd see the grey Tesla Logo indicating that higher automation is available if you want it on secondary, very minor streets, where before it only showed up on the Interstate.
4. If I actually double-clicked and engaged FSD on a secondary road, it would steer, stop, start, etc. in a distinctively herky-jerky style quite unlike steering and throttle I had experienced on freeways running under Navigate-on-Autopilot.
In sum, trust me, you'll know.