Black holes need not be dense. The black hole at the centre of galaxy M87 has the density of air in our atmosphere. The larger the black hole, the less dense it is. So that alone doesn't preclude us existing inside of one.
That’s news to me, I was taught that the mass collapses into it self it creates more gravity and more matter gets sucked in because the mass is so dense. So at which point does it become less dense?
As long as it’s dense enough that light can’t escape, it’s a black hole. You can achieve that with extreme density or huge volumes of mass. The more massive an object, the less dense it needs to be to be a black hole.