Too early to feel baby?

I'm now 15 weeks through my pregnancy, baby is due the 29th of December. I read that you don't really feel the baby until 16 - 25 weeks and seeing as this is my first pregnancy I was really expecting to feel anything until closer to 25 weeks. 
I know that every pregnancy is different and I've been told that the baby is very active from the midwife. But for the past 3 days I've been feeling a very faint popping sensation. As though something is tapping? If that makes sense. I was just wondering if anyone else has experienced this before at such an early stage?