First Ultrasound

I was very excited to get my first ultrasound on Father’s Day! The nurse said from the size of the baby then it seems like I was only halfway through my seventh week (my estimate was 8 weeks). The heart rate of the baby was 143.. is that good or bad? Sorry I’m a first time mom and literally get concerned over everything! Also does anyone have any predictions of the gender with the Ramzi Theory? It is killing me to know the gender!