Question about personal references when ordering a birth certificate and/or passport.

So I was born in London to a British father and an American mother. We moved to the US when I was very little (in the late 70s). I have always meant to formalize my dual citizenship and am working on it now. I need to get a copy of my birth certificate first. I have everything I need for that but am not sure on the non-family personal reference. Why do I need this for just my birth certificate? They only ask for a name and no contact info so I’m not sure how much to think about it. The person I have in mind is having some health issues right now and I can’t reach her to confirm that she’s cool with it.

I realize they’ll ask again when I submit a passport request and maybe it’ll matter more. Hopefully this one old friend works out but I also wonder, if I didn’t have friends there to vouch for me, would I be less entitled to my own birth certificate or a passport?