With a college degree, specifically a Computer Science degree, you generally expect a certain level of competence in CS fundamentals. E.g. the recipient will know about Big O notation, will be able to do problem analysis and design, and understand programming principles like heap memory, object methodology and concepts like memory pointers.
That doesn't take four years. Most of it can be learned in a year. (Source: I did.) CS degrees teach you things like computer architecture, operating system, relational database, networking, etc. which are nice to have but optional.
If you do well in high school you can obtain a lot of college level general education credit and knock off a year.
The last 2 years are probably more like what you did in 1 year.