I think there are a lot of factors that go into this: Would you be able to write about yourself in a way that other people would want to read about you? How much time do you have for writing this that you aren't already spending on something else? Can you think of anything about yourself that you would want to write about? In what style would you be presenting the narrative about yourself? Most importantly: do you want to write this?
I think "do you want to do it?" is the biggest question. Maybe the only one that matters. I mean, whether or not you have a super interesting life (if I wrote a book about myself it'd be boring as all hell ), and whether or not you can currently write well, and whether or not you'd be willing to improve as a writer -- none of that really matters unless you actually want to try the thing. None of us can tell if you it's something you want to do. If you do, go for it. As long as it's fun for you, it doesn't even matter if it's interesting or well-written.
Wait. The book is about you, or about them? If the book is about them - are you interested in them? (Is there a reason we can't be gender-specific here? The singular "them" is always a struggle for me. I'm going to assume this is a man who wants you to write about him). A book that contains only his "vital stats and stuff" would be very, very short and I can't imagine it would be very interesting. If there's more to it, and you're interested, go for it. If you're not interested but he'd be willing to pay you? Go for it. If there's some other concrete benefit from writing the book? Go for it. But writing a book about someone solely because that person wants a book written about him? That's weird. I don't see a reason to do it.
It's a book about them written from my perspective. Like, I'm the one recording all their vital stats (things like doors opened, boxes kicked, etc) but it's only going off what I know about them personally so I'm getting a lot of it pretty wrong. We'll also release monthly editions with updated information.
I'm just saying dumb shit, man. I have no idea why the OP made this thread or what they wanted to gain from it.
I'll play. What is it about you that they think is interesting to the point that they feel there should be a book written about you?