I have very bad night vision, and anything that is lit. I've always been light sensitive. What could cause this?

Many causes! Without an exam it is difficult to tell you what is going on. It sounds like you have always been this way, in which case it is 'normal for you'. Just like some people are cold sensitive (always need a sweater), some people are light sensitive. At the age of 48, you could also have early cataracts, which would decrease your night vision.
Many possible causes. See an ophthalmologist to find out what's going on.