TTC but....

Okay so we are super ready to TTC, but my dr said to wait until after I have one period before we even try. This is what he told me at my Mirena removal appointment Dec 22. I’m not trying to go against what my dr recommends, but do you all have any insight into this? We are getting inpatient in waiting and want to try asap but we also don’t want to cause any possible problems with the baby or the pregnancy.. any thoughts???