I dought that .. my wallet is 5 days old and open 4 days and never staked anything!
It depends on your balance/transaction weight. Obviously we can't reward a person with 1000xbc the same as a person with 1xbc.
There should be an estimated payout on the bottom right of your wallet if you hover over the mining icon (right next to the connections/sync).
it says ...
expected time to earn reward is 0 hours!
I have 90 coins in my wallet!
looks to me like its not staking!