Do you think FF is correct?

This month is a little less clear for me. Do you think I ovulated CD13 like FF says or CD15? I guess it could adjust the more temps I put in. I got my first positive opk CD13 but my chart looks more like I ovulated CD15 (and need more temps to confirm). If I take out the positive opk on CD13 (even though it is clearly positive) FF says it can’t confirm yet. I didn’t have any crosshairs, dotted or solid, until I added my temp this morning. Any opinions are welcome!