Plan B and ovulation & period?

I assume you mean you had sex on the 12th.
It's impossible to know what your chances of pregnancy are, as apps are just a guide/estimate. That close to ovulation, I'd always advise trying Ella, rather than Plan B, as Ella is the only emergency contraceptive pill proven can prevent pregnancy during the 24 hours around ovulation, itself, but even that isn't guaranteed to work.
Plan B works by delaying your ovulation. If it was too late to do that, then Plan B is unlikely to help.

There was another option of having a Paragard IUD fitted, as extra emergency contraception, but if this happened on 12th, then it's too late.

It's worth learning how to chart your fertility each day, so you know exactly when you are fertile.