I'm just like you with the self confidence. But yay for convincing people to go see the best live band ever!
As for going on your own, Ieen in i don't have any personal experience, but the smallest group I've bs with one other mate (RAH, 12th April 08). The other 2 Muse and 1 Oasis gigs were with double figures...
I would say that you would feel a lot better on your own standing rather than seats. If you can get Level 1/General Admission, then that's great as you can be on the pitch or in low level seating, and Level 5 seating means on the upper levels.
My first Muse gig (Wembley 17th 07 - HAARP gig) was about halfway up in the now expensive 'club wembley' area. The views were fine, and there wasn't any trouble with that, but if I had been on my own it may have been a bit weird. Saying that, you don't tend to pay much attention to anyone else while singing along to the songs, but it would be nice to have a mate there anyhow.