Molar cavity, help? :(?

I am 12 years old and I have a black cavity on my top molar, I don't remember if I had ever lost a molar in my life. I have no dental insurance so my dad refuses to take me to a dentist. Does this tooth with the cavity fall out!? or do I have it forever? Also my teeth aren't falling out as fast as an average 12 year olds should I still have quite a but of teeth that need to fall, help please
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The back top tooth should be either your 6 year molar or your 12 year molar. Both are permanent teeth and are meant to last a lifetime. You need to have it fixed.
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