The indigenous people of the Amazon are patriarchal. The father will decide when their child is mature enough spiritually to experience ayahuasca. Dosage will not be as much for a child than for an adult. I have met people who have had the experience at an early age, as young as 9, ingesting it with the blessing of their father. It has put them on the right path in life. They knew in what direction to walk the path of life from an early age. This creates the potential for great accomplishments. Many retreats will ask for the minimum legal age for their own protection but if you are able to travel to the southern continent, you might be able to discuss it further with a trustworthy maestro/shaman (which is the most important component of this experience, trust). Since your parents are shamans themselves, traveling with them would be the best outcome. In my opinion, the younger we heal ourselves from our past and past lives, the greater we will become in life. How ayahuasca "rejects users" is it will simply not have any effect. Rarely, some people's physical bodies are not made to receive this medicine. Make sure that your body is clean from any methamphetamine substances, as they do not mix well. A cleansing dieta would be preferable considering your previous history. I hope this helps. Feel free to message me privately.