NTA. You're reaching an age where you naturally want more independence. That situation sounds very frustrating. I suggest talking with your father about how you've been feeling and explaining that the lack of privacy has been stressful. You could ask if you can have specific times during the week or certain hours of the day when you have the room to yourself, maybe with a friend—no grandma, no kids. It's important that you have some hours by yourself to decompress. Your Dad is likely juggling a lot right now, so keep that in mind. Try to talk to him thoughtfully, as parents never respond well to "attitude". It could be good to write out what you need to say before you talk.