First ultrasound advice

So I received the referral today from my GP to have the first ultrasound (dating scan) - I asked her when I should have it and she said anytime from now. I'm wondering when I should have it - I'm 6w 3d at the moment but I'm thinking if I wait a few weeks I'll have a clearer ultrasound.

What do you guys think? Should I wait till I'm 8 weeks, or even later around 10 or 11 weeks? I'll only be having this ultrasound and the one at 20 weeks so just wanting to get a good timing for this one :)