Pregnancy after a miscarriage

So, I had a miscarriage back in December and just found out that I’m pregnant again. I’m obviously very excited as we were trying, but I’m also very nervous! I called to make my appointment with the OBGYN and they aren’t going to see me until 12 weeks. This makes me nervous because with my 1st baby they gave us an ultrasound at 6 weeks and with my last pregnancy I wasn’t supposed to be seen until 12 weeks and ended up bleeding a couple days before my appointment. I guess I am just wondering why do they wait so long?? I would just feel better if I didn’t have to wait that long 😩 I just want to know that everything is okay