HKCU registry and the start up application which one will ready first in windows8.1

I write a service to launch my appA to do something after the windows start.

question, When create a new user in windows8.1, AppA will be launced and read the registry at HKCU, but failed! Then I restart appA, read the registry again, it succeed!

I guess when the new user was created the appA was launched before the HKCU ready. Is it right？