Sealed Powers?

How would you know if you're powers are sealed??

if they have been sealed ur whole life then u would have had no knowledge of them but if u had them powers and then some one sealed them and u just did not notice then u could do a few things to find a way to get them back if they were sealed but powers do go away after a while there are people that could do somethings when at a younger age and lose that power as they get older