Doctors advice

Amber
Hi ladies. I just found out last Tuesday that I am having twins. I'm almost 13 weeks pregnant and have only seen a midwife once. Because of finding out that I am having twins I've had to find a OB/GYN instead of getting care at the birthing clinic. They scheduled my first appointment on aug 15, I'll be 19 weeks. Is that normal for having appointments so far apart with twins? 
I wouldnt worry except at the ultrasound the doctor said twin b had a little implantation bleed that the doctor might want to send me in in 3 weeks for another one. 
Any advice?