euripides
If you are under-age, you really have to live by the rules of your household. When you are an adult, you can run your own household, with your own rules.
Nisaba is right, you do need to obey the rules of the household.
Some people are really frightened of anything occult, and you need to respect that, too. I hope the books don't cause problems.
You know, as an adult, there's a lot of stuff that you keep to yourself. You don't share details of your personal relationships, and some parts of your life are very much separate. Often we work in situations, dealing with clients or students, where respecting confidentiality is important. So you kind of get used to simply not sharing things. You can share about Tarot here, and we're real people, so why share it with those around you? They don't need to know. It's a personal thing, like prayer.
Have you ever tried reading with regular playing cards? It's the same as reading Tarot without the trumps, and you just need to learn to read the pips. It's great practice for thinking about the numbers, and minors-only readings are actually quite good for everyday stuff, when you don't want the big spiritual dramas of the trump cards. This might be a good solution if you do need to stow your decks away.