be the first (person) to (do something)
To be very likely or eager to do something. You know I'd be the first to help you out; just ask me next time. She'll be the first person to admit that the program has flaws, but she still believes in it very strongly.
(be) the ˈfirst/ˈlast (person) to do something
be very willing or likely/unwilling or unlikely to do something: I’d be the first person to admit that I’m not perfect.Mary is the last person you’d see in a pub — she hates pubs.