It sounds like you are starting your period. Brown discharge is early bleeding and an indication of starting your period. It does not sound like anything is wrong at all. Are you worried about pregnancy? If so, do a home test.
Missing a period or having a late period is due to late ovulation This occurs from time to time for no reason at all. There is no reason to worry about a late or occasional missed period. It does not harm you in any way and is certainly not a medical emergency.
Yes of course, a variation in your cycle means nothing at all.
It sounds like a normal, but lighter period.