it's a pity offsprings who come to know something appliy it to themselves so easily. where are your parents dear. talk to them first they can tell you where to go. if i were a psychiatrist i wouldn't accept you in my clinic for start without being accompanied by your mother. at the age of 13 one can very well have mood swings this is part of adolescence, being moody because of hormonal balance etc...
seek the help of your parents first. the funny thing you say you believe you have bipolar disorder what makes you believe so. it isn't just mood swings it's mood swings as a result of a certain mental illness. seek counseling first
good luck
You havent given much info, perhaps if you let us know what happens when you have the extreme mood swings, really a doctor is the only one who can really ***** wether you have the bipolar illness and a phsyciatrist is the best equiped.