You can adjust the date and time settings in Date & Time Settings.
Set via Internet
|Set Automatically||When your PS Vita system is connected to the internet, date and time information is acquired automatically once a day.|
|Set Now||Your PS Vita system is connected to the internet and acquires date and time information.|
If you select this option, you can manually set the year, month, day, hour and minute (and AM and PM when using the 12-hour clock).
When you tap [OK], the date and time count will start from the hour and minute you set, and 0 seconds.