I went when I was 18. I took my bro and sister (they were my excuse to get some candy). I think only 3 homeowners asked me "Aren't you a little too old to be trick or treating?".
I will be going this year with my bro and sis as well, but I will not ask for candy...unless I have a baby in my arms
It's not about the candy for me. I just like Halloween and walking around seeing all the cool costumes. I can buy my own candy (safer that way too).