Suppose G is simple graph with n vertices. Prove that G has twice as many edges as vertices only if $n\geq 5$ I just didn't understand the second part of the prove

"G has twice as many edges as vertices only "... what do I actually have to prove ?

I understand it like $n=2e$ , is it right ?

then isn't it's just similar to the degree equation ??
When $n \leq 4$, the possible number of edges is less than twice the number of vertices. For example, when $n = 4$, there are 4 vertices but only 6 edges. In contrast, the complete graph on 5 vertices contains 10 edges.