"Simple virtual class room software" is actually more complex than, say, a full accounting package. I suggest that you learn proogramming first, at least, then learn a few computer programming languages, then decide which language you'd like to see the "simple virtual class room software" in. Then (remembering that it's FAR more difficult to analyze someone else's software than it is to write your own) I'd give it at least a few few years to "understand the source code"). (That's after spending about 2-3 years learning programming, and at least 6 months learning each language.)
This isn't a "get it, read it, understand it in a month" project you're looking at. If it's not terrifically overdocumented, it can take me an hour or two of intense study to figure out what i was even trying to accomplish in software I wrote only 5 or 6 years ago. And that's stuff I wrote - I don't have to try to figure out how someone else thinks. (People who take jobs to modify software that other people wrote - people who are no longer available for consultation - are usually working in rooms with rubber walls, doors locked from the outside and "assistants" who are large, muscular, and wear white outfits.)