I'm 25 also so i figure I might as well throw in my viewpoint.
I enjoy going solo. I've never done it all day - because it rarely takes all day to do everything I want to. I would suggest bringing a book or iPod if you don't plan on skipping long lines (I'm not really a meet you in line and talk kinda person, so I need something to feed my solitude I never get any wierd looks nor would really care if I did. Just go have a good time.