75th birthday holiday cruise 💃

Hello! I would like to plan a 75th birthday trip for my mom - a very youthful 75 loves cocktails, the pool, fun nights out, live music etc. I am thinking the holiday cruise out of Miami december 10-14. We both have ample travel experience but this would be our first cruise! Budget is in the 5-6K range. How do I move forward with a cruise travel agent? Also any thoughts on someone in their 70s taking this trip?

Thank you so much for your time :)