Uh, no. The first true Android tablet was the Motorola Xoom. The Chinese junk made with with the cheapest possible hardware, on ancient versions of Android, without Android Market/Play access, do not count.
Android 3.x was designed for tablets, blessed by Google for tablets, and granted access to the Play Store as an official device. Thats where the timer starts.
Ancient versions of Android? They were cutting edge at the time.
It wasn't Chinese, but made by the brand, that currently is the second largest seller of Android tablets in Europe.
Excepting the resistive touchscreen (which I personally like, way less accidental input), it was equipped with (then) state of the art hardware:
TI 800Mhz 65nm Cortex A8 cpu, 256MB of RAM, 3D acceleration sufficient to play quake 3, 32GB of flash, integrated GPS, support for parts of the 802.11n specification in the WiFi coded, BT 2.0....and all this in 2009.
And that's before I tell you that it could play back HD-video in 1080p via a separate HDMI dongle. And that there was a version released with a 500GB hard drive.
Sure, it had its faults (market had to be installed separately), but it was the concept of the iPad (let's make the iPhone big!) 6 months before that came on the market. At a third of the price.
That the Xoom only came out 18 months later is Google's fault, for not cooperating better with the avant-garde of Android tablets.
But an Android tablet is an Android tablet, and at least the original Galaxy Tab had probably more impact than the Xoom. The Xoom as Honeycomb launch platform was Google finally catching up, but I've not had problems with either my Archos or the Galaxy Tab, due to them using 1.6 or 2.0 Android.