So I'm from Utah, and I have loose plans of moving to Boulder county (Possible Grad Student at CU and job at Digital Globe in Longmont). I have 6 AR magazines all with capacities higher than 15. Can or can I not bring them in and use them?

A quick search will answer all your questions about magazines in CO.

There's nothing to understand. Nothing to know, nothing to do that would put you in jeopardy with the law
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There's also a few threads about the same question you've asked. Look up a few threads and here's one of 3-4. It's nice to know what one can do to keep legal. it's also easy to browse the COHTF and see who else had inquired.  
Any reason boulder cty?  Longmont also crosses in to weld cty.  If you're planning to rent. I suggest reading the other threads about Moving to CO also.

https://www.ar15.com/forums/t_8_20/588741_Magazine_question.html

Did your sarcasm break jim?

Only six mags? Amateur!!!!

The 'globe can be a bit of a sweatshop.  Plan to work hard.

The strictly-legal answer: if you owned the magazines prior to 7-1-13, it's perfectly legal for you to bring them. About the only thing you can't do is sell or transfer them in-state.If you got them after that date, they're banned unless you're LE/MIL/FFL.

The practical answer: nobody cares. Nobody is enforcing the ban. I would hare to violate COC by encouraging someone to break the law, so I'm not going to explicitly say that if you acquired one of the magazines on or after the magic date nobody will actually care.

It might be cheaper to live in Golden or on the Weld County side of Longmont and commute, but that's a separate story.

Commuting from anywhere in Golden to DigitalGlobe in Longmont would make any sane person want to eat a bullet.

Keep in mind DG Longmont will be moving later this year to re-join the mothership in Westminster.

The executive suite at the Westminster site is pretty sweet. Just saying.

(I don't work for DG)