Hi mama! Normal lang yan sa 16 weeks, kasi basta ang baby movements ay typically mas na-feel pa rin ng moms around 18-20 weeks pa talaga lalo na if first pregnancy mo, some of my mum friends didn't feel consistent kicks until almost 5 months pa. It's also possible na positioning ng placenta mo or kung saan ang baby is facing affecting how much you feel, pero since nag-worry ka na, best talaga na i-mention mo sa OB mo sa next check-up para peace of mind mo lang at just to be sure everything's okay. Hang in there, soon these kicks will be non-stop na yan!