I don't want to celebrate my birthday with my family
Why don't you want to celebrate it with them?
Nobody remembered my birthday
Things happen and sometimes family can forget. I am sure if you tell them it is your birthday, they will celebrate with you.
Why should I celebrate with those who are disappointing me?
You can give them a chance to not disappoint you by reminding them about your birthday. Or maybe they have not forgotten and are planning a surprise party for you. Either way, contact them.