Does any one know if Sylvia Plath had a brush with death at ten?

I am doing my senior project on Sylvia Plath, and as I was reading her poem "Lady Lazarus", it talks about how this was her third attempt at death. The first time she had been ten and it was an accident. I hadn't seen any information on any incident that would cause this to be true, but I just wanted to know if it was truth or just a fictional part of the poem.