Hi AzureMoonChild,
Breathe. You have your entire life ahead of you, and your mother's perspective is that she has very little time left to influence you ... parents love their children the best way they know how.
You cannot lose touch with your true self. Tarot cards, pentacles, stones, crystals, athames, candles, books, incense ... none of these make a witch, a Wiccan or a Pagan. And a witch "needs" none of these things to practice.
You already know your Tarot cards - you have a mental Tarot deck in your head. And you can recognize the themes and the archetypes, both Minor and Major, in the world around you, if you keep your eyes and your arms and your heart wide open.
Both you and your mother are reacting out of fear - she fears for your soul - and that is a very REAL fear to her. And you fear for your spirit. Breathe.
Think of what your mother's church looks like. Imagine sitting inside and look around at what is hanging on the walls and on the alter (if there is one). Imagine the pastor standing at the alter with arms raised ... hmmm. That looks like the Magician to me. Imagine an elder standing at the lecturn reading a passage from the Bible. Oh, there is the Hierophant. Imagine folks walking up the aisle to pronounce their Savior. Ah, the Six of Wands. Jesus? Well, the Hanged Man, of course. And folks gathering for coffee and donuts after the service? I always see donuts as pentacles for some reason ...
This is an opportunity for you to experience the cards, because the symbols (lions and fish and angels, oh my) are archetypal and speak to persons of many faiths.
You see things from your perspective; your mother sees them from her perspective. A good Tarot reader learns many perspectives. So, breathe, open your eyes, and know that your time to make personal decisions is coming.
Breathe,
Mnemosyne