If you're among the top in your CS course, then you probably have the skill-set needed to excel in technology-related fields and (possibly stereotyping here) may not necessarily be able to directly apply your skills to whatever good causes you're passionate about.

Get an awesome job to get rich then use your money for whatever causes you deem are important.

Your cause maybe the most important thing in your life but that doesn't mean you can't also enjoy a challenging job.