All I can say about swimming is that it takes a lot of time and patience to get where you want to be~trust me I know!!!
Just dont expect fast results because I promise they are very very rare!!!
When you swim don't be tempted to slack off! If you do I can promise that you won't see results! If you are a serious swimmer I also would like to suggest putting yourself on a weight training regiment( i have and since i have started my times have dropped drastically). Most of all have fun!!!