female pit bull

Question
My 10 month old pit bull has gone into her first heat, her vaginal area is a bit swollen, is this normal for this breed of dog?  I have never had a female dog, so this is new to me.  The area just above her vaginal area and below her anal area is also protruded a bit.  If this is normal, how long does it last?  

I tried doing a search on the web for information, but was unable to find anything of this nature.

Thanks for any help you can offer (in advance)

Answer
This is perfectly normal.  The heat cycle lasts 21 days. The swelling will begin to go down around the 15th day or so. Not all dogs are the same in this regard.  My I suggest that you have her spayed about a month after her heat. You'll have a much more reliable, healthy pet.