It's gouache on old paper. The line of dialogue comes from a fantastic 1960s Mills and Boon I got from Oxfam.
I did this very hastily, to take my mind off stressful issues of my own I am trying (and failing) to resolve! I also watched the Noah & the Whale "Five Year's Time" video on YouTube...it always makes me smile. Go on - try it! (I tried to put it in here - hopefully it's worked - if not - sorry!)