The phrase "admit upfront" is correct and usable in written English.
It can be used when you want to express the importance of being honest or transparent about something from the beginning.
Example: "I think it's important to admit upfront that we may face challenges during this project."
Alternatives: "acknowledge from the start" or "be honest from the outset".
I SHOULD admit upfront that I knew the thread was frayed.
Alright, I'll admit upfront that I'm a little biased here.
I will admit upfront – I am finding it hard to keep up with all the major moves happening in mobile and among the top technology companies.
I'll admit upfront that I'm not Nicholas Sparks' biggest fan.
I will admit upfront that I am not sure I have been able to describe this debate without my own bias interfering.
I want to admit upfront that I am biased; I have been publishing in multiple platforms for more than 20 years and am committed to unlocking the ivory tower of exclusive and expensive knowledge, sharing it with mass audiences through as many platforms as possible: books, film, television, radio -- and websites, blogs, e-newsletters and social media.
Olympic-watchers of yore admitted upfront that open-mouthed staring was one of the core purposes of the games.
Admitting upfront that they do not expect to win, conservatives are preparing to plunge the Senate into an election-year fight over a Constitutional amendment to ban gay marriage.
Posner admits upfront that his primary concern is how effective the spying is, and his New Republic piece criticizes the discussion of the N.S.A.'s warrantless domestic wiretapping as "aridly legal": This legal debate is complex, even esoteric.
A good rule for judging the ethics of your own behavior is whether you'd admit to it upfront, not whether you can do it well enough to get away with it".
He will usually admit to you upfront that he has commitment issues but he has worked on them and is "certain" he is ready to commit this time around.
