Just book it!!!!!
I went last year for the 40th Anniversary Cruise "solo"....had a nice roommate (Deluxe Verandah Balcony).
Met a bunch of gals and we've been to Sacramento and Palm Springs since the cruise. I was going "solo" this year,
until I mentioned it to one of the gals from last year and she said she was up to going with me. We moved up to a Superior Suite.
We are both "single"....so still part of the "solo" group.
You will have a great time; just open yourself up to it.