Theravada is the most conservative form of Buddhism in that it only accepts as canonical, teachings and Sutras that most likely go back to the original teachings of Shakyamuni Buddha. This purity is attractive but the 2500 years of development in Buddhism by many hundreds of enlightened teachers is for the most part ignored. Though we should revere Shakyamuni as a great spiritual teacher and the founder of this thing we call Buddhism, we also should recognize him as a human who was also limited and imperfect as all humans must be.
The nun said only one thing that I objected to. She gave the party line on reincarnation. She said that we will reincarnate again and again until all our individual karma is cleansed and then at last we no longer return. This is a very old idea, current in India long before Shakyaimuni and Buddhism. Shakyamuni asked us not to take any of his teachings as true until we have tested them in meditation or the other activities of life. Reincarnation is hard to test and Shakyamuni did his best to avoid talking about it. Only when pressed would he compare reincarnation to one candle lighting another, a very vague discription. Though we all want to continue in some way after we die and we also want to know we live in a moral universe I think it is better that this party line view of reincarnation be left out of Buddhism. It is not necessary.
In Zen a clear experience and understanding of our "True Self" is considered a mark of Enlightenment. Understanding our True Self is to understand our place in the Universe. With this understanding comes an understanding of what happens when we die. But this understanding is not about us as individuals in our normal dualistic way of thinking. The experience of Enlightenment is an opening into a non-dual experience and understanding of the Universe. This non-dual understanding is not in accord with the party line on reincarnation. Yet, reincarnation should not be completely dismissed, but rather seen through the light of the non-dual. This is poetic liberation. (See earlier blog). It is up to us as individual practitioners to test this understanding.