I agree with the other answers here. In particular, I follow the advice of @jakebeal where he suggests to put the acknowledgments in earlier on so you can account for the space it takes up.
I would like to raise an additional consideration for putting acknowledgments in earlier on: when your funding agency requires you to do so.
For example, in the US, certain Department of Defense (DoD) components (such as DARPA) require the authors of any publications (or manuscripts to be submitted for publication) stemming from funded research work to include an appropriate "distribution statement" at some location in the paper. In my subfield, authors typically put this statement in the acknowledgment section.
You might ask:
Why not just add the distribution statement in after the paper is accepted for publication?
Well, manuscripts to be submitted for publication must first be "released" for publication by the DoD, and if the distribution statement is not listed in the paper, then your paper is not approved for "public release." (You can get into trouble with the DoD if you try to submit your paper prior to obtaining public release approval).
Check with your funding agency to see if they have any constraints on the acknowledgment section (or first-page footnote, etc.) of your paper, and at what stage of the publication process it is required.