...rather than buy a place that you'll have to move out of in a few years because it's too small.
Your income is only going to increase, while your mortgage stays the same (if you got a fixed rate), so you are starting at your lowest point earnings wise.
You can hedge on a bigger house, too, by renting out a basement or a loft over a garage, and supplement your income.
Obviously, don't get crazy, but don't be too shy.