Coding is designed for all students - elementary, middle, and high school - as it builds on one another. Students do not have to start with Block Coding as a language. The content is not locked because Discovery Education encourages exploration according to skill and interest.
In the lesson plans, Discovery Education has provided some scaffolding for how the content aligns to US standards. You will find that Block ranges from grades K - 2 in the first lessons up to 6 - 8, Python starts with 3 - 5 and goes to 6 - 8, and HTML currently does not have standard alignment. For no coding experience, Block is always a great place to start, even if older than K - 2.