I'm going to ditch my own birthday party
It is supposed to be a joyous time, why would you want to ditch it?
The birthday party is... just another day in my life
I see your point, but it's rude not to attend a birthday party given for you. People want to celebrate your birth so it should be a happy time. However, if it is something you truly don't want, you should discuss that with your parents or whoever put the party together.
You are welcome to come but I will not be there.
It is rude to fail to attend a party someone made for you. You should feel honored and thankful that you are loved.