From center to point guard?!

1st of all, actually i dont hav to explain the phrase above... But today someone "arrrskkk" me what is mean by point guard... ARG!!! I though you watch slam dunk??? Maki, Fujima, Ryota are point guards!!! Still dont get it?? Their job are deciding what is the next move to offense... Anyway back to the topic, you guys told me that i have the potential to be a center... Ok... I think almost all of you will consider a person with 175cm or above to be tall... But on the other hand, in NBA, most of the point guards are 180cm or above, you get what I mean?? Most of the point guards are the shortest person in the basketball team, that means what we consider as tall person can be the shortest person in NBA... Isnt that a big difference?? In conclusion, I just want to know your point of view with this topic... To be honest, I prefer it to center as some of you who playing basketball know that playing as a center is a difficult job to do... =X