Hi. Girls, what is the deadline for registering? In my first pregnancy…

Hi. Girls, what is the deadline for registering? In my first pregnancy I registered at 6 weeks. Now it's almost 10 weeks since my last period, but there's war in the country and it's difficult to be outside the house. Thanks for your answer. And one more thing, should I go for an ultrasound first? What tests do I need to undergo?