Postpartum TTC no period yet...

My son is 13 months old, we just decided to try and have been having unprotected sex for over a year now just because my period hasn’t been back. I didn’t get my period back with my oldest until almost 18 months... really don’t want to wait that long to have another baby. I guess I just wonder how to know if it’s even possible to Conceive right now..I have been trying to track my CM and cervix so far. I feel so lost!!! Oh I forgot to mention this will be my 3rd baby!