What are the events on the timeline of my children’s lives that have the most impact?

I would say all the events are equally important. Because a child develops different aspects and build his/her character based on all the events that take place in his/her life. When they are babies and toddlers, they are trying to make sense of the world around them and developing and learning new skills everyday. At school going ages, they acquire knowledge of the world and try to find their sense of being and how they fit in. Every experience they have would shape their values and their character. A parent's role, in my opinion, is to help guide the child and provide support whenever needed. If I were to try and identify a time that has the most impact, I would probably say during the childhood period. This is where values can be imparted, which can help guide them in life. Just my two cents.