Question about due date!

Courtney • 21. Married to the love of my life. 💜 Noah AuG 2016 💙💙 TTC #2 with PCOS & Testicular Cancer💚💚
Hey ladies I'm just curious about your opinion (: 
So my last period was October 22 to 24th. No period in November and didn't get a bfp until December 18th. I got a bfn December 10th. 
Based off my last period I'd be almost 10 weeks? What do you think???(: