Hi JaiJoli, voters are selected at random, not everyone who enters will be selected to vote. The only people who are always selected to vote are Aediles and above.
Aediles are part of the Senate, which is the site admin team. This page has more information.
As far as having always voted previously, there are currently a relatively low number of active members, so it's probable to be selected to be a voter a lot of the time, but not guaranteed for every time.
Thank you.