Make sure ALL the ports show the green light in the dedicated server launcher.
ALSO, make sure ports 27015 and 26016 are BOTH forwarded correctly for both TCP and UDP protocols. Both of them are required for Steam in-game server browsing.
Age 0 is a known bug when the game fails to create that SQL entry in the database and is DISASTRUOUS to keep arround when you have stuff like building and thrall decay turned on in the server settings. You can fix the Age 0/Age ?? bug by following this guide:
Also, as the host, you will NEVER be able to connect to your server using the in-game browser, if the server is running on the same PC or on a PC linked with you on the same network. It will ALWAYS show Age ?? and PING 9999 for you in that case. You will need to use direct connect and use the IP the server is hosted on. You cand find which IP the server is on using what is shown in the Dedicated Server Tool, under the “External IP” field. Copy that IP and add the port after it using Direct Connect inside the in-game server browser in this fashion: xx.xx.xx.xx:port
Just make sure other players (that are not on the same network/LAN as you) that they can see the actual age of the server and proper ping. Any player connecting to the server through LAN needs to do the Direct IP connect method.
Hope this helps!