Can’t predict dpo based on line darkness since people implant with more hcg that others to start and people’s hcg rises quicker than others. Basically someone at 8dpo could have more hcg present than someone at 11dpo. Congrats!

Hcg doubles every 2-3 days so you are def past 11 DPO based on when implant occurs and how quickly hcg rises. If you implanted at 6 DPO (absolute earliest) by 9 DPO you would have a faint line and 2 days later a bit more noticeable but this is way dark haha as the PP said it does vary with each pregnancy but this looks dark. Congrats!!!!