Looks like mine with this one, at supposed 10dpo they were so faint as to be almost invisible, at supposed 11dpo they were just visible and bHCG was 16, and they slowly got stronger, my next BT at supposed 15dpo was 68.

With DD my tests look very similar too, though from 15dpo onwards, bHCG at 16dpo was only 29, late the next week it was only 711 I think, and 1.5wks later it was only 15700 or something like that and DD is now 8 months old

Congratulations are in order