Certifications for engineers, particularly for CAD, are much less important than technical coursework/engineering work experience. There are still firms out there who use dedicated drafters, and it's hard to know where you will end up.
I've also never seen it happen that a summer intern or full-time person didn't get hired simply because he or she didn't have experience in a particular drafting program. In comparison, I can say engineers have definitely NOT been hired based on technical coursework and previous work experience. That's not to say learning the CAD programs where you work isn't important, just that it's usually not the basis for a hiring decision, so it should not be your primary focus.
I will also second the comment about which civil engineering field you are pursuing. For one example, if you are going structural buildings (where I've been for 10+ years), I'd learn Revit instead, particularly how to create a model and export it to the structural analysis software.
To be honest, if you used the time you had allocated to gain the certification, to instead apply it to some part-time hours working in a relevant area during the school year (TA job, work-study program, co-op, etc.), or even interviewing professionals who are already working about their career paths/what they wished students knew before they started working (which has the double benefit of expanding your network for your job-hunt), your time would be better spent.
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Stephanie Slocum P.E.,M.ASCE
Founder
Engineers Rising LLC
www.engineersrising.com------------------------------