I don't unrstand "set aggregated-devices ethernetdevice-count number"
The ae interfaces are automatically created by Juniper when you set the "aggregated-devices ethernetdevice-count number" .
You can configure as many as you want(supported number) but they will only be active when thecount match that number. So it starts from ae0 - aex. if count is set to 1 then ae0 is created, count set to 2 then ae0 and ae1 created and so forth.
show interfaces terse | match ae
And see if the interfaces you want are members of ae11; it will show you what is up and the protocol running
Also >show ethernet-switching intefaces