Hello and Welcome Smudger 
I would suggest get the brochure or look online to see what is on offer, then pick a destination you always wanted to visit.  I chose Jordan as my first Just You experience because I always wanted to see Petra.  Since Jordan, I have been to Andalucía, Costa de la Luz, Israel, Italian Dolomites and Croatia, Calabria, Istanbul, Troy & Ephesus and Marrakech for Christmas last year.  I am going to Namibia in May and have a long bucket list ready! 
Happy travelling. 
Jaya