Which Est. Due Date?

My doctor's due date based on LMP is 1/24, but my date based on ovulation is 1/27. Both ultrasounds have lined up with my ovulation date.

Should I adjust my brain to think of myself as 15w6d, or keep my date as 15w3d?

My cycles are irregular, which is why I always track bbt. I've had three babies and I've been 4, 8, and 4 days late.

I'm thinking I'll just keep my internal date, but then when I meet with my doctor I get thrown off. Plus I don't want to be discouraged when I'm late again.