Are you referring to start time or latency, or both? Start time is how long it takes for a user to start seeing video after starting playback. Latency is how far behind the stream is compared to the encoder.
If you start Wowza in stand-alone mode [install-dir]/bin/startup.bat|.sh, you should see lines in the console like this. Please post what you see for these lines:
How are you testing? Is it local or remote, is it iOS device or HLS desktop playback with JW Player or VLC?
You can reduce the bitrate of the stream. You can remove network factors if you are testing remote to see what the delay is without that. Understand that iOS devices need 3 chunks before playback, so if the bitrate is very high and the device is remote and a slower connection, it still has to download 3 large chunks.