Wrong due date???

I went to my very first ultrasound at what I thought was only 4w1d (yes super early but I see a fertility specialist).. anyway, I ended up measuring at 5w3d.

I don’t understand how I’m measuring over a week ahead? I know the exact day that I ovulated. Could this just be a mistake? Or can it just mean larger baby? I know it’s too early to even think about it too much.

I thought my due date was May 2nd but apparently this is an April baby according to scan 😮