7 + 1 but measuring 6

Claire • 31 years old ttc with my partner of 9 months after being friends for 15 years. Spent 3 years on the implant with no cycles. First cycle arrived 28 days after removal and hoping to fall pregnant soon x
Went for a private scan today as I'm quite anxious . According to lmp I should be 7 weeks and a day but baby measured in at 6 weeks. It had a heart beat of 122bpm which I was told was strong and everything looked well. Should I be concerned about the size of baby tho ? Anyone else had this ? X