To inform oneself

I don't think we have an exact equivalent of that; so your sentence makes sense but isn't idiomatic (ie. it's not something a native speaker would say).

We do have the expression "educate oneself"; so you could possibly say

I first have to educate myself on that before I can make a decision.

or, without the reflexive,
I'll have to research that first, before I can ma

[nq:1]I don't think we have an exact equivalent of that; so your sentence makes sense but isn't idiomatic (ie. it's ... . I'll have to gen up on that . . . I'll have to check that out . . .[/nq]
Personally, I have no trouble with the phrase "inform myself"; but as Peasemarch has pointed out, all these expressions seem to go better with some kind of complement ("on the subject", "about the matt

[nq:1]find[/nq]
I have no difficulty at all with the original usage as formal English; in fact, I think it's normal, if we recast the sentence as "I shall have to inform myself before I can make a decision". "I first have to..." isn't idiomatic, but might possibly appear in speech; "First, I'll have to..." and "Well, first, I'll have to get the details.." and "I'll have to get the details firs

I cannot explain why, but to my ear "I have to inform myself" sounds pompous.

[nq:1]Is it acceptable/common to use "to inform oneself" in the sense of "to find out" (German: sich informieren) e.g. in sentences like: I first have to inform myself before I can make a decision.[/nq]
It would be more idiomatic to say something like, "I need more information before I can make a decision."
You can, however, inform yourself about a particular problem.

Steve Hayes