Yes that's about right.
But you can start doing the basics before then. Like getting them to follow you around, doing front crosses and changing sides, changing pace etc.
And you can start training equipment too.
Just set jumps, tyres etc. to lower than their elbows, and make sure it is on grass or equivalent. You can set dog walk to really low, usually without the ramps, and A frame just lying on the ground. Basically so the dog just gets used to it.
NO WEAVE POLES though until they are much older.
You can also teach them tricks, and get them clicker trained, which makes training oh so much easier.
Get them to touch a target on the ground with their nose, for contact training. Get them used to using their back legs as well, by getting them to put the front legs on a small square thing and then rotating around it.
Buja board, get them used to uneven surfaces, for the see saw.
The list just goes on.
There is more to agility than just jumping over things, also set points and w thingys to teach them how to jump properly, and getting them to drive to objects, like toys, food on plate, etc.