Hi Charley,
Nice to see you on the pregnant side of the boards
I think it is usually around 19-20 weeks for a first baby, however I felt my son at 16+6 weeks. This time I have an anterior placenta which cushions the movements so it took a little longer to get the really strong movements.
I would say I had slight flutters around 17-18 weeks but I only recognised them because I had been pregnant before. It was really the 20 week mark when I was 100% sure. 
It won't be long for you.... (and then they get really full on and you wish it would all calm down as you push feet out from under your ribs etc )