Im a 27 year old CS student. By the time I graduate, I may be 30 something. How much does age impact my chances in being hired by a tech company?

You'll get a job honestly and you're not too old mate

Similar situation here - working part-time as working student with a company you're interested in might help.
Also I know some guys who finished their CS studies way beyond 30 and were employed right after. The companies that deem you too old won't hire you, the rest might not even care.

It depends on how much you advertise it && if you look your age. I finished my master at 33 and I couldn't find a job for two years. Whenever I would have an interview and age was brought up, people would take a pencil and note it on my CV. I got my first and current job cause I look younger than the recruiter assumed I was and he found about only when I sent him the papers for my contract. Funnily enough, my project manager commented about my age today while we were going to our main client, curious why I finished my studies this old. It's up to you if you want to hide your age or not. From my experience, I wouldn't mention it unless I had to.