I personally don't think it's strange at all. People have certain things that they like/like to do. Some people take football the same way you take Halo. Others are obsessed with Call of Duty, Gears of War, God of War, Bio Shock, resident Evil etc etc...the list goes on. Some people harbor their obsessions in different ways. I just hate hearing people say how its not normal or stupid or that person is crazy. To me it just boils down to living your life and being happy with what you have and what you can do to make your life better for yourself. It sounds selfish, yes, but not as long as you leave some room in your life for the ones you love like family husband, wife etc....I hear this kind of talk from people I work with that when I first met them would "understand" armoring/really loving something like the Halo universe, but of course that's just asking to much to ask/expect. Again, this just boils down to the high school nerd/jock mentality IMO.
Hell, I am 29 years old and still playing video games! I am married and I am so glad my wife gets me lol! But as long as you are responsible, who gives a rats a$$ I say more power to ya! and rock on!