It is a gamble, and depends a couple of issues.
Are you sure that you will go to grad school within 5 years? If not it might all be a waste of time and money. Even if you do, are you going to go to a full-time program that requires the GRE or a part-time program that doesn't? And will you be able to get an acceptable offer within 5 years, or are you going to take two or three admissions cycles to find the "right" program? It is hard to forecast what will happen in your first five years out of school.
Do you have trouble on these kinds of tests? Most engineers do fine on the quant portion but struggle on the verbal and writing sections. In many cases people do better during or immediately after school because the general education requirements of the school have forced them to do more reading and writing than they would normally choose. Conversely, if you are someone who reads recreationally and does not particularly need to study for the exams, waiting might not be any real penalty.