bitrex, passion and joy are more important than achievements. If you totally enjoy math or related areas,such as Computer Science, go for it, and achievements will evolve over time. I were doing almost nothing till I turned 26, then realized math is a great thing. Now, five years later I'm still extremely humble (you can easily check by my questions on MO and MSE), but aeons ahead of myself when I were 20, my brain functions much better and I'm working towarrds an advanced degree in CS. If it is someone around you that keeps telling you off, have a closer look at what they do and why you should listen to them at all. In the end mathematicians live a long happy life unlike many others.