I share iTunes with my son, he is 18 but some apps I own I don't want him to download or see in iTunes. Right now we share the same account and I want him to have access to all movies, music, and most apps.
A separate iTunes account would work, except there would be some paid apps, music and etc. you would have to pay twice for if you both wanted that item. Also, if you go with separate iTunes accounts, you might want to change your ID password. If he knows it now, he could still log in to your account and see your purchases.
Note: iOS 8 will take care of iTunes sharing, so separate accounts would work.
Sent from from my ancient but trustworthy iPhone 5