Being able to accurately forecast how long software tasks is definitely a skill a leader in an engineering team needs. I'd say it's good to know the accuracy of your estimates - I'm not sure you need to sweat speed of development. Often software tasks take as long as they take... and speeding them up can have some really adverse effects - like poor quality.
Over time, it's good to have a general sense of how long certain kinds of work take, and where the surprises can be in building estimates. No estimate is perfect, so knowing factors that contribute to error is easily as important as being right about estimates.
Since I can't quite tell - if you're concerned that your not getting work done in a timely manner - the best thing to do is check out your work habits and the time to complete of your peers. Are most people on the team taking about the time you do? If you're spending more time in certain areas, ask why? And be alert to any habits that aren't contributing to getting stuff done... we all have some slack in the day, but you want to make sure you are consistently getting ahead.
Ironically, one of my preferred ways to procrastinate is in task management - I like planning and replanning work... and I get so caught up in that, I can fail to get things done! :)