Am I allowed to have privacy?
I’m technically an adult (19 years old) and my parents are always asking where I’m going, what I’m doing, etc. and sometimes I don’t want to tell them.
Do I have to tell them?
As long as you’re not doing anything wrong or to be ashamed of, why would you not want to tell them what you’re doing?
I mean, there is a difference between a parent’s simple or polite curiosity to want to know what’s going on in their kids’ lives out of care and concern for them---- and being prying, demanding a detail-by-detail account of every second of your life. You don’t specify which kind of asking is going on, and I would say that the latter kind
would be inappropriate for parents to expect of their adult and reasonably-responsible children.
I’m one of those adults still living at home in my mid-twenties; they pay the bills, i pay my own basic expenses (food, gas and car costs, pet care, etc) and clean up after myself, etc around the house. Since my mother and I share the car that’s technically mine, it’s important for us to have at least some general idea of who needs to be where and when, for scheduling purposes. If I have many errands to run I usually don’t specify each and every stop I’m making, but I would never just take off without telling her that I’m leaving (she’d worry about me). And it goes the other way as well.
So, I don’t know what the situation at your place is like, but maybe they are just being typical concerned parents who want to still be a part of your life even though you’re an adult now— which is wonderful. Think about it from their perspective: it must be hard for them to see you all grown up after having been “their baby” for so long

. Surely it’s not that big a burden for you to keep them in the loop of your activities in return for everything they’ve done for you and for continuing to live under their roof.
If they’re being truly intrusive, however, then you should try discussing it with them in a mature, non-confrontational way explaining that you appreciate their concern, but it makes you uncomfortable now that you are an adult that they still treat you like a child. If they know you to be trustworthy they’ll understand and respect your needs, as you should in turn respect their natural parental interest in you.
On the other hand if you are not being responsible, then no, you shouldn’t expect them to support you in whatever way without knowing what you’re doing with your life.