Ovulating and implantation close to period?

Kara • Trying for baby #1. Ttc for 1 year.
So I heard that if you ovulate close to ur period n if it gets fertilized n implants close to ur next period it won't work? Idk if that's true. Maybe someone can back me up on that. But I'm worried that I ovulate late. A couple ppl told me I ovulated on the 17th or 18th from my bbt chart. But my periods r usually between the 23rd-27th. It varies month to month between those dates. If anyone could help n give me some info that would be great! Thanks :)