Hindi pa talaga nararamdaman ng karamihan ng moms ang movements ng baby sa 13 weeks, usually around 16-20 weeks pa lang when first-time moms start to feel something, lalo na if first pregnancy mo! Pero if you do feel some fluttering or movements, that's totally normal din, bawat baby and every mom is different, so walang masyadong specific "standard" sa ganitong early stage pa. If you're worried about anything or gusto mo lang ma-confirm na lahat OK with baby, best talaga to check with your OB para sa peace of mind mo, especially since early pa lang ng pregnancy mo.