Q.  I am going bananas in Harry Potter's magic.  I believe in everything, yet I have doubts.  It's too late for me any way as I am 13 and have received no letter at all.  I want to be a part of Harry Potter's magical world so badly. Is Hogwarts real, will I still get a letter, am I a witch, will I ever be a part of it?  Will I see Hogwarts beside the times that I see it in my dreams?  Will I be able to go to Diagon Alley and get my first wand, does Diagon Alley really exist?  No answer will change my beliefs, yet, if you answer me the way I hoped you will, it will make my determination even more and make me more patient to wait for the right time to come.

A.  When is something real and when isn't it?  Not everything that is real can be seen and experienced by our 5 senses.  There are things and places that are outside (or some say along side) of ordinary reality.  Hogwarts is such a place.  Does it exist only in the mind of J.K. Rowling and her readers?  Many people, both children and adults express the kind of deep longing for Hogwarts and the magical world that you have expressed here.  Can we long for something that doesn't exist?  Perhaps our longings indicate that something within our very being reaches out to that "something" in the other world.  Religious people would say that the very act of longing is a sign that something else does exist.  I think that Hogwarts is a metaphor for that which does indeed exist in another plain of reality... a deeper reality than that which we see around us.
-------------------------------------------------------------------------------------------------------------------------------
Visit Order of Merlin for your wizard supplies.