以前 (いぜん) has two distinct usages in Japanese: a straightforward temporal meaning ("before") and an emphatic meaning ("before even getting to that point" / "far from"). While the temporal sense is common at all levels, the emphatic usage is characteristic of N1-level grammar.
In its basic sense, 以前 refers to a time before a certain point – "before," "previously," or "formerly." It can be used with specific time references or on its own.
When used with a noun or clause, it takes the form Noun + 以前 or V[dictionary form] + 以前に.
At the N1 level, 以前 is used emphatically to express that something doesn't even reach the level being discussed – the situation is so far from a certain standard that it's not even worth considering that standard. This usage often appears in the patterns ~以前の問題だ ("it's a problem that comes before even ~") or ~以前に ("before even getting to ~").
In this emphatic sense, the speaker is saying that the topic mentioned is premature – there is a more fundamental issue that needs to be addressed first. This carries a tone of criticism or frustration.