Ok, the usual way to determine how fast you swim, is 1
lap.
Normally, 1 lap-50m, takes an average swimmer using br-eaststroke
1min.
For front-crawl, about 55s.
You can try to use more of your arms to bring the water to the rear
when you swim. Also, instead of 1 stroke 1 breath, for the
beginning 20-25m, you can take 2 strokes, 1 breath.
Also focus on your leg kicking, this can increase your efficiency
very much. In essence, try to bring your body as horizontal as
possible when you swim, rather than your front body close to water
line, and your waist and legs under the water. This creates a lot
of resistance. 
