Bbt chart understanding

Madeline

Hello I’m trying to figure out when I ovulated based on my bbt?

Based on Opks my peak was the 19th from my understanding you ovulate 24 to 48 hrs after that now I guess my question is can bbt help narrow that down? So I can know how many DPO am I? Also can bbt charting help to know if you are pregnant or if I should test for pregnancy?

Also can the dip on cycle day 21 be implantation?