Do you already know how to code, and how computers work? If no, take computer science. You're best starting early.
Do you have any economics education yet? If so, you probably know what you're missing.
OTOH, if the rest of your schedule is really heavy, you might consider taking the course you're already stronger in, to give yourself more time for the rest of your course load.
Both topics are really important and quite interesting, and both also tend to veer off into no-longer-business-applicable abstrusities at the higher levels.
Also, you might want to mention what university you're at. There is a huge ideological rift in economics right now, in a way that isn't true for computer science; the person who's teaching your economics course could have a pretty substantial impact on whether you come away with a warped view of how economies work.