Aww first time mom ka pa lang, kaya normal lang mag-worry! Hindi lahat ng oras active ang baby, lalo na kapag gabi, marami sa amin ang napansin na mas tahimik sila pag tulog na or pag late night, kasi minsan napapagod lang din sila o nasa position na hindi gaano ramdam ang movements. But you know your baby best, kaya if you're noticing na talaga namang less active than usual or kung feeling mo may different pattern, better check with your OB lang just to be sure, hindi harmful at makakatuwa lang ng peace of mind mo, especialmente pag first time ka pa! How many weeks ka na ba, by the way?