Also if you tracked your periods before getting pregnant then you will see that the luteal phase (second half of cycle after ovulation) is always the same number of days. Your ovulation can be later which makes it seem like a late period but my luteal phase was always 13 days and the range from beginning of cycle to ovulation varried between 16-18 days. But you can always call your dr if you are worried about it and unsure why you havent started again.
If you ovulated late, then you will see your period starting later. Ovulation determines when you'll get your period, and your body needs at least 10 days after ovulation before your period will start (luteal phase).
I wouldn't worry about it too much, after a miscarriage your cycles can be a little irregular for a few months.