I want to purchase this game but don't know how many blocks it takes. and how old should you be to program or to start?

It takes less than 1000 blocks. About 600, if I recall correctly. There is no real entry age for programming. As long as you can use a computer and you are willing to learn, you can code.

Software itself is 89 blocks, 100+ with updates. The Extra Data storage, as far as I'm aware, sizes itself based on how many files you save.