What cruise line would be best for a high school graduation cruise with my mom?

[SoccerStar234]

For my graduation gift my mother wants to take me on a mother/daughter cruise. We have been researching for quite a while and feel as though we don't fit into any of the categories (i.e. family, couples, singles, etc).
Any experienced cruisers want to suggest a cruise line that you think would be best for us? Thank you!