OPK/Temping clarification

La

Hi ladies! Wondering if I can get some input here. My husband and I have been "just seeing what happens" for 3 months. September is my first month trying to chart BBT, use OPKs and checking CM. I was pretty in tune with my cycle before this month but I want to make sure I'm doing this accurately to keep track of my cycle while TTC.

I got a positive OPK on CD 15 and a spike in my temp of .43 on CD 19. I was NOT temping at the same exact time over the weekend as I had been during the previous week. Will that effect the accuracy of my BBT chart?

Based on what I've read on glow and a book I bought, the spike in temp just confirms ovulation occurred. Is it typical to see a spike 4 days after seeing your + LH surge?

Thanks for helping me understand. I have photos of the charting I have done if anyone wants to look.