Played without linking PSN account to VITA

So when i bought my ps vita 3 weeks ago i had this promote asking me to either sign in with an existing account or open a new one - i declined both options so it gave me a "dummy account" - i can browser PS store but cant play multiplayer .

Now, it also gave me "parental controls" app since i entered a date of birth - required also for a dummy account- that is under 18 and i have been wondering what happens once i open a new real account on the system . Will it let me open an account that is over 18 ?

And also , will trophy information saved on the system transfer to the new account?

Just to make something clear.I am not signed up to PSN in anyway on my VITA , I can confirm that it even asks me to sign i or sign up with a PSN account in cases in which -let's say- i want to buy something from PSN or something like that...

Will the current trophy info saved on the system delete it self once i either sign or sign up with a PSN account?

Trophies are linked to accounts, so I don't think they will carry over to whatever new account you put on it. I can't really answer any of the other questions, since I've never had to mess with underage accounts/parental controls.

Do you have a PSN account on PS3/PS4 that you use? If so, then you should just put that on the Vita. If not, then make a new account that you want to actually use instead of messing with a dummy account or whatever.