Should I take the GMAT before investment banking?

I am a senior about to graduate with a 3.8 GPA and a degree in Finance from a top 25 school. I worked in IB this past summer and am continuing on with the same bank doing tech m&a full time. I do not know what I want to do after banking, but want to leave as many doors open as possible. I was thinking about studying for and taking the GMAT now so that I can put as much effort in as possible while I have free time without the distraction of full time work. I'm not sure if I will want to go to B school, or if I will in the next 5 years (how long GMAT scores are valid for to my understanding). For someone coming out of a top private school straight into IB, is there a strong reason to get an MBA this soon after graduating? Is it worth studying for and taking the GMAT now or am I stressing out for no reason? Thanks!