Quick preface: I’m not sure if I’m balding or not.
Anyway, I notice when I shed hair, which I don’t do excessively, a lot of the hairs are random sizes. Some are equal length to the rest of my hair, others are smaller but still as wide,
others are longer but thinner, some are shorter and thinner etc.. Is this ever the case in normal shedding or is it always an instance of MPB causing miniaturizing?
Normal shedding at the end of the anagen phase should push out a normal width hair in over 90% of the hairs that you see. If the hair are largely miniaturized, then maybe you do have male pattern baldness (MPB). Most men lose their hair from balding without noticing it, because the hairs die at the end of an anagen cycle and do not grow back.
For more on hair growth cycles, see Hair Follicle Cells Growth Stages.