Does it matter what age you enter the computer science field, lets say 30, trying to work for google or another big name with no previous experience in programming?

In terms of the expectations of your potential employers and fellow employees, not really: the big name companies are relatively egalitarian places.  But overall, yes: it's an uphill battle at best and the odds are against you joining one of those companies.  My reasoning: The big name companies recruit only the best CS candidates.  If you have no experience in programming, you will need several years to obtain training, probably at a top school.  That's another 3-4 years of your life and tuition money.  They will be very intense years in order to get the grades and experience you need to get your foot in the door. You slow down in your 30s and beyond, both in mental flexibility and physically.  Personally, I can't keep up with 20-somethings anymore in terms of sheer code output.  I need my experience to compete, and I'm only 35.  I can't imagine how it's going to be in another ten years. The 20-something person has a longer career in front of them and more potential.  That reason is why most top MBA schools don't take candidates significantly above the age of 32. As mentioned, people in their 30s have more responsibilities.  Everything else being equal, employers want the 22-year-old that stays late at work, not the 35-year-old that has to pick up the kids at 5pm. I know one exception off the top of my head: she received a PhD from a top-5 school well after the age of 40 and worked for Intel.  She was single the entire time.  So it is possible, but your life will have to be pretty much like a 20-year-old's to make it work. All that being said, even if the big name companies don't take you, if you can operate close to that level, you will never have to look hard for a job in the major tech cities.  The demand for skilled programmers far outstrips supply, and because you can pick your jobs, you'll probably find them enjoyable and rewarding.