I have just received an appointment for my 20 week scan which I have had to reschedule as I'll be on holiday. The receptionist at the hospital wouldn't let me reschedule for when I get back saying that it would be too late for my 20 week scan. So I now have an appointment next friday when I will be 18+2- is this going to be too early for the sonographer to do the full detailed scan and to sex the baby? I only had my '12 week scan' last week