Hi there, our daughter was diagnosed just before she turned 2. Having to learn so many new things can be overwhelming. In new Zealand they put out a really helpful book for parents of children with diabetes. While we were in hosp getting kaitlyn stable - learning how to manage her diabetes felt like the most important study I've ever done. These forums are a good place to learn and receive support from others who understand.
Highs have no immediate risk - uncontrolled highs over a LONG period of time cause complications due to nerve damage - I find the most helpful way to describe this to people is basically - when there us too much glucose in the blood the blood gets sticky and sticks to the nerve endings building up over time and causing damage and loss of function.
Lows are a more immediate danger - lows untreated promptly will quickly cause loss of consciousness followed by coma and worse case scenario - death. That is why we need to check levels regularly and any time where our child is sleepy or clammy or so forth - you will have been given symptoms list to watch for. The only way to know for sure if levels are good is to test.
It is better to have highs than lows. And as you learn how to manage her and what to look for things will get more and more stable
There is no such thing as perfect when looking after a child with diabetes - there is too much unpredictability! Focus on progress not perfection. Be kind to yourselves and take one step at a time.