You mentioned that you have not started although you have the intention to do so.
In this case, your use of present perfect continuous tense is not appropriate (I've been going). Present perfect continuous tense is used for an action that started in the past and is still ongoing.
Since your intention to start jogging started half a year ago and you still intend to do so, you can write: For the past six months, I've been planning to start jogging the next day.
In this way, it is your intention to start that is ongoing, but the action never started.
Hope this helps.