Periods can be late for a variety of reasons, and even the most regular of woman can have an off cycle. Periods can be late because of stress, changes in routine, mood changes, new exercise protocol, illness, weight gain or loss, etc. A lot of reasons, our hormones can shift and we get these issues. In my 20's, I had two things that made me have periods every 3 to 4 months for a year and a half. I had a hormonal imbalance of natural production of too much estrogen (as found in blood work) and I had hypothyroidism. Those were resolved and I was regular ever since. Have you had any sexual activity? If you've had sexual intercourse, then go ahead and take a pregnancy test to rule that out. Otherwise, wait until the three month point and then consider going ahead and calling your doctor. I was at the doctor's office recently and found that they very much try to keep everyone safe. They kept me in the car and texted me when it was time to come in so no one was in the waiting room and no one was walking in at the same time as me, they all were masks and social distance and they sanitize like crazy. An ob/gyn is best to see and they have even less covid type scenarios in their office. So, don't neglect your care . At the very least, they practice telemedicine and you can discuss after a full three months have passed why you are having such a long cycle.