Well, you weigh roughly 55 kg, and a few days ago I took about 210 mg and I weigh 70 kgs, so it was roughly 3 mg/kg, and I have 0 tolerence, never taken it before, and got a mild high, but was still a good one. You need at least 2 mg/kg to get anything at all, and even then it won't be very much. Take more.
Assuming you're not enzyme-deficient, which you don't appear to be given the lack of discernible effects, the problem is that you took a dose that would only give you the barest of periphery effects. I'm NOT suggesting you take more, either, as DXM has a limited appeal for many people. Good reading is the DXM FAQ, which can easily be found by typing in those words to a search engine. Do a lot of reading before embarking on a DXM voyage.
You didn't feel anything because you barely hit a first plateau. If you're going to do it again, research what would be a good dose for your weight. If you aren't looking for just a simple high, maybe off-balance and feeling a bit tipsy, then I suggest trying enough to get you to the LOW second plateau.
Take it slow. DXM is one of those drugs where you either like it or you don't.