Both commuting and bring a mature student will most likely change how you experience university. However I think the understandable anxiety most mature students feel before starting exceeds the reality. I felt the same when I started, but the other mature students on my course immediately gravitated towards me and we've been friends since.
Do look to get involved in things. If going out at night is difficult due to the commute, look for daytime stuff. Also look into the mature students society at your university. The one at my university often goes for coffee together, where we sit around bitching about lectures and how kids today have such atrocious taste in music.