Early scan info UK

So I went for my early scan today 7+2 days and the sonographer said all good , dates are pretty much spot on n HB looked good but I still feel petrified n feel like she didn’t tell me something!!

Would they tell me if something wasn’t right???

When she was measuring everything one measurement I noticed said 6+5 days , n others 7+1 n others 7+2. Is this normal to have mixed dates at different measurements. But she never made a point of it & at end said yeah your dates are good 7+2.

I briefly remember when I was preg with my daughter that each scan 9,12 & 20, different parts measured differently but still scared!!!

Help please?????