I started domaining in April (I bought my first domain in March and the second in April actually). But as you can see I am a member here since January. And on other forums too.
I made 400% of my initial investment. Always by finding niches that others forgot. Maybe after two years people will say "oh I came too late, in 2007 there were still available LLL.in 's or LLLL.com 's".
I also try not to start buying all sorts of domains, but I stick with some niches that worked. LLLL.com 's are doing great for me, and cctld's are also great (while I agree with sdsinc that cctld's are not for starters, I started with that and had a jackpot with it).
It is never too late, but always think forward. Do not register everything you see (it is a common mistake), but make a list of 50 - 70 desired fresh regs and register only the best 2 or 3.
Alex
