Letter to my future self

Hi coaches,

I just listened to this week podcast on gifts to my future self where Brooke suggests to write a letter to our current self from our 10 years from now self. I was wondering if you are supposed to come up with precise facts about your future self like exact job, exact income, number of kids, their age, my partner job, if we’re married, the city I live, what my house looks like, if my parents are still alive,etc or if we are supposed to stay vague about our future life.
The reason I ask is I feel weird imagining my life in so much details when so much can happen in 10 years and some parts of it I won’t have control over so I can’t really anticipate it. Should I imagine the perfect life I would like to have 10 yrs from now? But what if I don’t quite believe yet this perfect life could become true? I feel like I would be fooling my current self talking as a fulfilled future self I don’t really believe in…

I really like the idea of this exercise and building a relationship with my future self. I just want to make sure it is authentic.

Thanks for your help!