My little miracle

Baby's heart beat was 160 no chance of ds an baby is decoupling great an is healthy I feel great i just had miscarriage in June so this past 12 weeks I've been a bsll of nerves im glad I made it to my second trimester !! According to the app your 2 nd trimester starts at 12 weeks or at end but im 12 w 1 day Sn it said I've reached the 2nd tri