Bipolar disorder is not something you can diagnose yourself. This is something a psychiatrist diagnoses. So if you feel that you need to get help, instead of telling your parents what you think is wrong with you, how about you tell them you need help instead. Good luck.
my older sister has bipolar disorder and she is now 24 but she was diagnosed when she was 15. but she went to boarding school and didn't get help until she was about 20. she is now dying because she didn't get help and it turned her into a drug addict. she hasn't been herself since
i suggest you get help now because I'm 14 and if i were you i would have a serious talk with my parents to prove to them and go to a therapist