When to test?!!

Jessica • Wife, daughter, sister, friend, and mostly Mother.
Okay... So I am almost positive I had implantation bleeding. Rusty colored d/c for two days that didn't even need a panty liner. My husband and I aren't trying hard to conceive like we did with our son (who is 11 months old today 😩), we just aren't preventing it. It took us THREE long years to get pregnant with him. So we figured it would be best for our baby (who was EBF until 6 months) and best for us when we are ready to actively try to conceive again to not use birth control. That all being said.. We BD on Friday the 5th which was my most fertile day. I had this d/c on Monday and a little on Tuesday. I'm a little excited but not trying to get my hopes up because of our past fertility issues. When can I test?! Other side notes, I NEVER have had spotting and I didn't have "implantion bleeding" when I got pregnant with our son. Please help!