Spacetime is expanding at a very high rate. In that expansion the light emitted had a larger space to cross in order to get here. Therefor it would take longer for it get here than just the 5bn yrs. I been reading your comments and some of the folks here have been giving you great examples and explaining things perfectly. It is hard to grasp some of this if you are not a Physics/science major. Take a few entry level Physics classes, shit watch the new Cosmos show(or How the Universe Works is a great one) and it'll even put things in more basic terms to understand this. I am not being a dick by saying this. I said the same thing to my mother about 15yrs ago on taking a Computers 101 class so she could get the basic usage of a computer down and it worked wonders for her. This may very well help you understand this wonderful universe we live in. :)
OH OH, there is also a lecture on YouTube, by Neil deGrasse Tyson, search for "My Favorite Universe" in youtube and it should bring it up. It's a 12 part series. He also has a more current one on Netflix. I can't remember the name at the moment, but it is 6 parts.