It's a pleasure to be of help, Holly
I am in my mid-40's and I used to be on the ships years ago when the 'old and rich' dominated the passenger loading. That has thankfully gone now and the cruise lines are evolving...it does have to be said that they cannot afford to aim at specific age groupings anymore, they need backsides on sunloungers and those backsides are of all ages...ships nowadays, even the older vessels are catering for all ages far more than they used to.
There are child-free ships around too if you really don't want to be cruising with the rugrats that belong to other people. Everyone is covered now...there are so many ships out there that offer a variety of things to do (or not, according to what you want out of a cruise).
Please do not hesitate to ask if you have any other questions or concerns
My TA has just returned from Splendor's naming/inaugural and as most people have already mentioned...she is very pink but she caters for every age group....because she HAS to in order to survive the massive competition that she has out there