Calculate how many weeks I am?

Anne • Due date 10/8/20!

Hi! I got a BFP at 12DPO and again on the day my period was supposed to start (yesterday). I’m hoping for guidance figuring out how many weeks I am:

Last period first day: 12/24/19

Average cycle: Ranges, but the last one was 35 days

Ovulation day: 1/15/20

If I calculate it based on my last period first day, I’m 5 weeks. But I’m wondering if it’s more like 4 weeks because my follicular phase tends to be a bit long and my luteal phase consistently 14 days. Thanks in advance!