Songs are not autobiographical. They can be but that is not the point of a song. I read a quote in a book by Pat Pattison called "Write better lyrics." He said, Never let reality get in the way of truth. The emphasis of a song is telling the truth. Or maybe it might be the way that I see truth. I have an example from my songwriting of how this works.
I wrote a song called, " How to fish". The story is about going fishing with my Grandpa Cowhick. There are some lines in my song which are not accurate. The first line of the song is, He taught me how to row a boat. Okay, he didn't really teach me how to row a boat. We didn't have a boat. Now if we would of had a boat, he might of been the one to teach me. The truth is I went fishing with him and a I learned how to fish from him. That is the truth.
I do like that opening line. How many of us remember the first time we tried to row a boat? It is really difficult if you chew gum at the same time. It takes awhile to train your muscles to do movements that are new. Does it really matter to your audience, the color of Grandpa's shirt, if the sun was really shining that day or whether you owned a boat? If the accuracy of these details really matter, then go ahead and write your autobiography. I hope this helps the next time you go to write a song.