Typicaly type 1s are. Diagnoses as children and they are Insulin requiring. Type 2 tend to be adults and overweight and have are non Insulin requiring.
Used to be easy. Decades ago it was rather easy, any non-adult was likely a T1-which is why they labeled it juvenile diabetes. T2 was usually overweight older adults (we called it adult onset). Now with the emergence of serious obesity at earlier ages we see T2 in some overweight teens. The terms changed. Testing is sometimes needed to sort out all the overlap but now below teen years its likely T1 while later??
It varies. Type 1 diabetics are usually children, but can include some young adults. Type 2 diabetics are usually adults. However, type 2 diabetes is usually caused by obesity and we are starting to see some obese children develop type 2 diabetes.