Python in Uru is pretty simple, you can get a great grasp of it by reading some of Cyan's code. For starters, you might look at something like xAgeSDLBoolShowHide.py
However, I'll summarize some things here.
Python classes used in Plasma need to derive from ptModifier or ptResponders. ptModifiers are usually only reffed from the plSceneObject while ptResponders are usually called through complex logic interfaces.
In your class, you can override the following methods
OnServerInitComplete
This is called when (in multiplayer) you are done talking to the server and the script is loaded.
OnFirstUpdate
This seems to be called sometime after OnServerInitComplete yet before linkin occurs
OnSDLNotify
This is called when an SDL Variable that you have registered for notify is changed
OnBehaviorNotify
This is called when a ptAvatar who you have registered for behavior notify has done a behavior
OnNotify
This is called when a registered notify (ptAttribute i.e.) throws a message
OnTimer
This happens on a scheduled time from PtAtTimeCallback
Anyway, those are the basics. There are a few more methods that you could use, but they're likely not to be too useful right now (I don't see you needing to fetch the public age list)... Have fun!