5w2d just had my first US

Yuyu • My baby boy was born March 23rd, 9lbs, 53cm 💓 a really awesome baby
Hi all I just had my first appt with my Obgyn... Went well... Doc said I'm 5w instead of 6w due to my long cycle. So the sac is 1.2cm long.. And the baby is tiny tiny ... Only 0.2cm... And she said we may not see a heartbeat yet.... BUT! during the US I saw a HEARTBEAT already !!!!! Feels amazing... Is it normal to see a heartbeat when the baby is so small?