Is plan B for sure effective?

Okay so long story short me and my boyfriend were having sex or whateva and when he came, suddenly the condom broke too as he pulled out. So he doesn’t know if he came in me or not and we’re not about to be teenage parents we we quickly went to target and got PlanB one step. I took it within an hour of having sex, and there a 98% success rate within 24 hours, so wouldn’t it work even better if it was just within an hour? I’m not really stressed, but I just wanna be sure